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tips on building a 383 sbc stroker

PostPosted: October 9th, 2008, 10:43 am
by grumpyvette ... 82&sr=8-11"] John Lingenfelter on Modifying Small-block Chevy Engines (0075478012381): John Lingenfelter: Books ... 809&sr=8-2"] Smokey Yunick's Power Secrets (9780931472060): Smokey Yunick: Books

buy these book/video's its probably the best money value you can get, you might be amazed at what a couple hours research into the subject will do to help you build a much more durable engine, and actually reading thru links and sub-links and asking questions helps a great deal


viewtopic.php?f=44&t=38 ... 383_cu.htm ... education/



milling stroker clearance on 350/383

viewtopic.php?f=51&t=7697&p=26187#p26187 ... clearance/ ... ewall.html



youll need a decent value in a less expensive yet stable engine stand ... _200305217

all these threads add useful info on your parts selection


viewtopic.php?f=52&t=5078 ... alance.htm ... rminology/











viewtopic.php?f=69&t=2378&p=6279&hilit=hemi#p6279 ... cation.htm









I know some of you guys would rather pluck your eye out with a red hot fork, rather than read links and sub links but for the few who want to learn...









viewtopic.php?f=71&t=741&p=1048#p1048 ... index.html

here high lights, or cliff note version


place a single rod/piston assembly with well oiled bearings and use no rings installed on the piston,in the first cylinders bore , be sure the crank journal,has old bearings well greased in the rod your using to get the clearances and have the cam installed to check clearances, also, you don,t necessarily need to degree it in, correctly a dot-to-dot install on the cam will give you a good idea on clearance work. ,now, rotate the crank thru a couple full rotations so the piston slides freely in the oiled bore, while you look closely at the rod too block clearance and rod too cam lobe clearance, if the cam lobes are too close the edge of the rod bolt upper/edge ( no less than .080 thousands, is ideal) of the rod bolt or the rod itself needs to be filed/ground for clearance since you can,t grind the cam lobe, on the block the block gets clearances ground, you want about a .060 minimum clearance. a large paper clip can be used as a crude feeler gauge,
a 1/2" diam carbide cutting burr in a die grinder can do it in seconds,once that's done you move that piston & rod to the next cylinder and repeat 7 more times, etc. don,t forget to clean up afterward,with both a strong magnet, and a pressure washer and solvent or at least high pressure air, and DON,T forget the rod and piston has the exhaust/intake valve and rod bearing radius fit correctly in only one direction on that cylinder, so youll need two rods/pistons, a left and a right for the clearance work,

read ... index.html
use a good 7-8 quart baffled oil pan
keep in mind the (H) style rods and the CAP SCREW designs generally have more clearance than the stock bolt/nut design rods, and theres are stroker rods designed for max clearance

when building a 383 stroker ,you need to check rod to cam and rod to block clearances, you should have not problem grinding .080 or so clearance on the lower bore wall edge with zero chance of getting into the water jacket passages or water jacket at the area of the yellow paint indicated in that picture, most people forget to check that area
obviously youll want to check all 8 cylinders and remove the cam and clean carefully before re-installing the cam.

Small Chevy

Fastener Type Torque Spec

7/16 in. outer main cap bolt 65 ft.-lbs.
7/16 in. inner main cap bolt 70 ft.-lbs.
3/8 in. outer main cap bolt 40 ft.-lbs.
11/32 in. connecting rod bolt 38-44 ft.-lbs.
3/8 in. connecting rod bolt 40-45 ft.-lbs.
Cylinder head bolts 65 ft.-lbs.
Screw-in rocker arm studs 50 ft.-lbs.
Intake manifold bolts (cast iron heads) 30 ft.-lbs.
Oil pump bolt 60-70 ft.-lbs.
Cam sprocket bolts 18-20 ft.-lbs.
Harmonic damper bolt 60 ft.-lbs.
Flywheel/Flexplate bolts 65 ft.-lbs.
Pressure plate bolts 35 ft.-lbs.
Bell housing bolts 25 ft.-lbs.
Exhaust manifold bolts 25 ft.-lbs. ... ch-part-1/ ... ch-part-2/

Big Chevy

Fastener Type Torque Specs

Main cap bolt, 396-427 2-bolt 95 ft.-lbs.
Main cap bolt, 396-454 4-bolt (inner/outer) 110 ft.-lbs.
3/8 in. connecting rod bolt 50 ft.-lbs.
7/16 in. connecting rod bolt 67-73 ft.-lbs.
Cylinder head bolts, long 75 ft.-lbs.
Cylinder head bolts, short 65-68 ft.-lbs.
Screw-in rocker arm studs 50 ft.-lbs.
Intake manifold bolts (cast iron head) 25 ft.-lbs.
Oil pump bolt 65 ft.-lbs.
Cam sprocket bolts 20 ft.-lbs.
Harmonic damper bolt 85 ft.-lbs.
Flywheel/Flexplate bolts 60 ft.-lbs.
Pressure plate bolts 35 ft.-lbs.
Bell housing bolts 25 ft.-lbs.
Exhaust manifold bolts 20 ft.-lbs.

IF your going to use ARP main cap studs THE TORQUE SETTINGS ARE DIFFERENT than the original BOLTS, the STUDS ARE STRONGER, BUT,you might also consider that main studs generally install after cleaning the threads in the block with a tap,blowing them dry with high pressure air, oiling the studs course threads with the thread sealant and fine threads end with the ARP thread lube, when you screw them into the block the full thread depth,by hand, then get backed out one turn, the main caps installed and the nuts torqued in stages to seat and hold the main caps, now LOOK at those STUDS the end in the block threads is SAE COURSE thread, the end your torquing the nut on is SAE FINE THREAD with a much differant PITCH that requires less tq to give the same clamp loads
AND yes it very common for the stroker crank, counter weights or connecting rods in a 383-400 to touch a 350 oil pan, and make a ticking or knocking sound, if you don,t clearance it a bit more, with a ball peen hammer on the oil pan rail area, Id also check the dip stick as some touch the rotating assembly
for obvious interference, youll need to check this, it can be made to clear rather easily but it must be checked and properly fitted/clearanced


Why do they get backed out by one turn? I'm trying to think of the physics behind it, but I can't think of any good reason. What is the physics answer, Grumpy?

the threads must bear evenly and align correctly with the studs center line, for the stud to apply max loads over the total threaded surface ,the threaded section must be under tension alone and engage the total threaded surface in the block, if the stud is torqued into place, you've preloaded the threads bearing the load and they are partly under compressive loads ,your basically jacking the bottom of the threaded hole away from the threaded section, and applying THOUSANDS of lbs of extra stress to the blocks web area if you torque the threads to the same 100 ft lbs the original bolts were tightened to, the threads in the block will now have added stress once the full tension loads on the studs and main caps is applied by torquing the nuts on the studs ,theres added stress on the block, if the studs have bottomed out and are pushing on the bottom of the threaded hole making the block web area more likely to crack or the crank saddles to distort.
keep in mind FACTORY BOLTS are made slightly shorter to PREVENT the bolt tip bottoming out in the hole, but bolts cause wear on the threads because they are tightened while the bolts still advancing deeper into the threaded block, studs cause far less wear because they fully engage the threads bearing the loads before the tensive load is applied

heres what ARP says

ARP recommends the use of main studs over bolts whenever possible for several key reasons. First is the ability to obtain more accurate torque readings because studs don’t “twist” into the block. All clamping forces are on one axis. By the same token, there is less force exerted on the block threads, which contributes to improved block life (very critical on aluminum blocks). Finally, there are factors of easier engine assembly and proper alignment of caps every time"

ARP's instructions (for head studs)state that you should thread the studs into the block until they're hand-tight, but with the head on the block, this is difficult. Fortunately, ARP was thoughtful enough to incorporate a fitting for an Allen wrench into the head of each stud. So, using an Allen wrench, I threaded the studs into the head until I could no longer turn the wrench with two fingers. This method seems to have worked nicely

1. Clean and chase appropriate threads in
block to ensure proper thread engagement
and accurate torque readings.
2. All hardware (and caps) should be
cleaned and inspected prior to installation,
looking for any shipping damage or defects.
3. Screw studs into block, finger tight
ONLY. For permanent installation, apply
Loc-tite (or similar adhesive) sparingly
to threads. Be sure and install the caps
promptly before the cement sets to prevent
misalignment of studs in block.
1. Clean and chase appropriate threads in
block to ensure proper thread engagement
and accurate torque readings.
2. All hardware (and caps) should be
cleaned and inspected prior to installation,
looking for any shipping damage or defects.
There are a number of important considerations
when installing ARP main studs.
3. Screw studs into block, finger tight
ONLY. For permanent installation, apply
Loc-tite (or similar adhesive) sparingly
to threads. Be sure and install the caps
promptly before the cement sets to prevent
misalignment of studs in block.

First and foremost is making sure the
block and studs are as clean as possible.
Foreign matter and debris can easily affect
the quality of thread engagement and
cause erroneous torque readings. Do not
re-cut threads in the block – use the special
“chaser” taps as listed on page 87 of this catalog.
This will preserve the integrity of the
threads and provide better engagement.
Calibrate your torque wrench – even new
wrenches have been known to be off by as
much as 10 foot pounds! Use consistent
tightening techniques.
4. Install main caps, checking for binding
and misalignment. Lubricate threads, nuts
and washers with oil or ARP moly assembly
lubricant before installation. Note that torque
specs will vary by lubricant. Moly lube is
most consistent. Have block align honed.
5. Using the instructions provided with
the studs, tighten the nuts to proper
torque values three times. NOTE: If using
Loc-Tite or similar cement, proper preload
must be achieved prior to it setting up.

removing the rod caps during clearance checks while building your 383 ,does seem to allow you to see the clearance issues a bit easier


yes the cam lobes can very easily contact the connecting rods when the cam index is out of its proper timing, on almost any chevy engine the cam lobe center lines will be spaced at between 103 and 116 degrees, with the piston at TDC theres SUPPOSED to be about .060 MINIMUM clearance between the connecting rod bolts and cam lobes, this is a mandatory clearance check point and a plastic cable tie can be used to gauge clearance, its best done on each individual connecting rod to cam lobe clearance point AFTER the cams been degreed into the block as each connecting rods being installed but Ive generally done it during the several trial assembly points where I check other clearances like block to connecting rod clearance.

thats why on some stroker crank engines a SMALL BASE CIRCLE cam is used to MAXIMIZE CLEARANCE,between the two moving parts.
a cams lobe lift is the difference the lifter moves off the cams base circle between its base circle and its max lobe lift, thus a cam with a 1.1" diam base circle and a .400 lobe lift would have a , .400 lobe lift and if you had 1.5:1 ratio rockers a .600 valve lift, but if you wanted more clearance you could use a smaller base circle at .900, and a 400 lobe lift this would allow the connecting rod, to sweep by with an additional amount of cam lobe to connecting rod bolt clearance, the change in diameter generally requires a swap to a stronger cam billet core . vs cheaper cast core,to maintain cam strength
the cam rotates while indexed by the timing chain at 1/2 crank shaft speed , there are connecting rods designed to provide additional clearance.

I usually use this sealant (sparingly)on the course ends of main cap studs that screw in hand tight, and ESPECIALLY on head studs that enter water jackets


keep in mind the course thread section is not being screwed in or the threads moved as the nut on the fine thread upper end is torqued to spec. and that thread requires the ARP thread lubricant to get the correct stretch and that stud needs to be cycled up to full torque then released and re torqued,a minimum of three times to get the stretch/tq correct

I got asked recently what hydraulic roller cam ID suggest for a street/strip 383 combo?(obviously theres a wide selection that may work,)

ONE GENTLEMAN pointed out ,after shopping around one of the least expensive deals seems to be the EDELBROCK CAM BELOW

SB-Chevy 283-400 Hydraulic Roller Camshaft Kit

Duration Advertised 296° Intake/300° Exhaust
Duration @ .050'' 234° Intake/238° Exhaust
Lift @ Valve .539'' Intake/.548'' Exhaust
Lift @ Cam .359'' Intake/.365'' Exhaust
Lobe Separation Angle 112°
Intake Centerline 107°
Intake Timing @ .050" Open 10° BTDC
Close 44° ABDC
Exhaust Timing @ .050" Open 56° BBDC
Close 2° ATDC

IVE used similar cam designs (duration/lift/)in the past with excellent results and $709 for the cam, roller lifters and push rods is a good value, naturally the REST of the components and the cars drive train and the cars intended use will effect the choice
the only thing that makes me hesitate is the quality of edelbrocks cam cores.AS most IVE SEEN are not billet but cast cores which are less durable and on a 383, PLUS you want a small base circle cam......for rotating assembly clearance issues ,one reason I usually suggest this cam in similar combos

your cams lift is the result of the lifter movement distance from the cams base circle, where the valves seated to the point where its fully up on the nose of the cam lobe where the valves at full lift.
lets say in this case we compare two imaginary cams
a standard cams base circle is 1.125" and
your cams running on a .900 base circle
both cams have a .560 valve lift and run with 1.5:1 rockers
so both cams will need to move the lifter .374"
that means the standard cam lobe will be 1.125"+.374" or 1.499" from the cams base to the cam lobe nose
that means the small base cam lobe will be .900"+.374" or 1.274" from the cams base to the cam lobe nose
which is significantly smaller

Grind Number: HR-230/359-2S-12.90 IG
Operating Range: 3000-6500 RPM
Duration Advertised: 292° Intake / 300° Exhaust
Duration @ .050'' Lift: 230° Intake / 238° Exhaust
Valve Lift w/1.5 Rockers: .539'' Intake / .558'' Exhaust
Lobe Separation Angle: 112°
Max Lift Angle: 107° ATDC Intake / 117° BTDC Exhaust
Open/Close @.050'' Cam Lift: Intake - 8° BTDC (opens) / 42° ABDC (closes)
Exhaust - 56° BBDC (opens) / 2° ATDC (closes)

with either cam you'll want a 3000rpm stall converter , about 10.5:1 cpr and a 3.73-4.11:1 rear gear to maximize the performance and a low restriction exhaust, headers and a high flow intake

IM currently running the crane 119661 cam in MY 383 and Ive tested over a dozen cams in that engine, so if its a street/strip combo ID suggest going that route, SMALL BASE CIRCLE AND BILLET CORE.....yeah! YOU GET WHAT YOU PAY,FOR and DURABILITY FOR PARTS TENDS TO COST MORE
IVE dunked my piston/ring assembly's in a can of MARVEL MYSTERY OIL just before installation with a ring compressor and have never seen the slightest indication of problems either on ring sealing getting the rings broken in, or on tearing the engines down later for inspections

remember that when you go to re-install the compressed piston rings, and piston in the engine block,bores that dunking the piston in MARVEL MYSTERY OIL , just before, its slid into the ring compressor will coat the rings and bore contact areas enough to prevent many small problems that insufficient lube might case

Re: tips on building a 383 sbc stroker

PostPosted: October 9th, 2008, 10:44 am
by grumpyvette
BIGGER is NOT always BETTER, and since both the header primary diam. and length and the collectors , which have a huge effect on the resulting scavenging can,t be changed as we change engine rpms, we need to maximize the cylinder scavenging characteristics so as to maximize the cylinder filling and extend the rpm band of the torque curve but once your have the collectors and headers primary designed to maximize the scavenging in your chosen and intended rpm range and run the collectors to a (X) to induce both increased scavenging and lower restriction to flow theres not much that a larger exhaust past that point can do badly but increase the noise levels while it should be rather obvious that a smaller than ideal exhaust will hurt the upper rpm band as it tends to be a restriction
yes if you have a smaller exhaust diam. it tends to act like an extended collector and increase low rpm torque at the cost OF being A restriction ONCE THE RPMS BUILD PAST A CERTAIN POINT.having both collectors empty into an (X) pipe EFFECTIVELY instantly doubles the cross sectional area of the exhaust pulse and significantly reduces the return reflected pressure wave, almost making the collectors act as if its running without any restriction compared to a true dual exhaust IF the exhaust pipes are large enough to provide a very low restriction at that point

theres plenty of fluid dynamics math and research out there to show that the distances the exhaust travels between exhaust pulses and the diam. and length are easily calculated, and past that length the second previous pulse has little effect compared to the current and previous pulse energy and reflective wave
and lets not forget the cam timing displacement and intake port all effect the cylinder scavenging the headers can effectively provide also

Gen.I, "Medium Journal", includes "Vortec" 305 and 350 thru '98

obviously youll want to check clearances with plasti gauge once the bearings are available also (READ THE LINKS) and use assembly lube on the bearing surfaces during assembly, you can clean them out of the box with a lint free cloth and a bit of diesel fuel then install them, check clearances , and use assembly lube before final assembly but it looks like youll have clearance in the correct range if you get the correct bearings

reading these threads, and sub linked info, will provide a great deal of additional info, youll want later










Be sure that you check and re check/ verify the QUENCH and PISTON TO VALVE CLEARANCE during the pre-assembly process.







LETS ASSUME I WANT MY 383 TO MAKE MAX POWER IN THE 5000RPM-6300RPM BAND (mostly so I can run street gears and pump high test gas and a low maintenance hydraulic roller cam, and IM willing to sacrifice a good deal of street drive-ability to maximize my corvettes track potential)

using the above calculators we quickly find I should have about a 3 sq inch intake port cross sectional area, the exhaust should be about 39" long in the primairy 1.825 dia,and about 18" -20" long in the collector, about 3"-3.5" dia.
a matching compression of about 10.5:1-11:1 and a cam in the 230-235 durration range at .050 lift, heads that have the same 3 sq inch port and flow about 280cfm this will tend to maximize the power at THAT rpm band, and ideally a 3.90:1-4.11:1 rear gear ratio and a 3000rpm-3500rpm stall converter
but that above will NOT work nearly as well as a smaller and less radical combo in the 1500rpm-4500rpm most cars spend 90% of their time in
its all a compromise and most people don,t realize how miserable that combo will make the daily driven car that rarely get above 4500rpm, where a smaller and longer exhaust would scavage more effectively but give up some of the potential for max power when the cars raced

your 100% correct if you were looking to cruise at 2500rpm , the cams above will be a P.I.T.A. on a car designed mostly for mid rpm cruising, you could get good performance from them but the street manors in traffic will be less than ideal....certainly manageable but not exactly smooth

you'll be far better off with something similar to these, if street manors and low to mid rpm cruising are a higher priority, but have a LONG talk with the manufacturer of your choice about your combo and expectations before selecting your cam and matching your combo gearing and compression, head lift restrictions and flow characteristics

ZZ-9 Hydraulic Roller:
Intake Exhaust This is an emission legal cam which makes
Advertised Duration 282/ 287 over 400HP with our CNC"D LT heads and
Duration at .050 212 /226 F-car headers. Great with an auto or six
Gross Lift .483/.520 speed.
Lobe Separation 112

BTW if you get some light smoke from the exhaust the first time you start the new engine,thats not uncommon.
hold a sheet of typing paper in front of the tail pipe and have a buddy lightly rev the engine, you'll quickly see if its just condensation moisture or coolant or oil film.
Once your sure of what your dealing with you can locate the source.
if its condensation from parking in a cold garage or outside it should get burnt off in a few minutes and not return after brief times parking, that won,t allow the exhaust system to fully cool.
BECAUSE it a new rebuild IF its a light mist of oil smoke it should get much lower in duration after you take the car for a high speed trip of an hour or so too seat the rings and valves fully, drive it like you had get out of state before the ex-wife finds out you won the lotto, and the rings should seat quickly

Re: tips on building a 383 sbc stroker

PostPosted: October 9th, 2008, 10:47 am
by grumpyvette
GOSFAST posted this great photo to illustrate the differance between rod designs


rods designed like the 3 SERIES generally won,t work with stroker cranks while the 2 series usually will

the connecting rods you sellect make a huge differance in the rod to cam lobe clearance, even a small base cam won,t clear some designs, it should be obvious that the connecting rod with the thru bolt has a great deal less cam lobe clearance potentially than the cap screw design next to it., and the cap screw rod probably clears the blocks oil pan rail area easier also

Im running that crane 119661 cam retarded 4 degrees BTW but detonation has not been a problem, remember that the coolant temp, air temps the engine sees, QUENCH distance, type of head gasket and its construction ,ignition advance,plug heat range,piston to bore clearance, exhaust valve seat width, and oil temp and pollishing your combustion chamber and piston domes, and your AIR/FUEL RATIO , and the effective DYNAMIC compression ratio, have a noticable effect on detonation

and if you do see detonation, theres octane boosters like TOULUENE
many guys don,t realize that the rod bolt material and cross sectional area are critical to durrability , especially in a high rpm range combo,while the rods themselfs ocassionally fail, its much more likely that the rod bolts lost thier clamping strength, stretched a bit first and that was a major contributing factor in the bearing failure or the rod failure process.

one reason I prefer a using a dremel tool,while I work near the cam tunnel doing clearance work and removing casting flash, and not my die grinder that I use near the block rails grinding rod clearance or in most of the block clearance work, thats not near machined surfaces, is theres less potential to damage machined surfaces if you get careless or slip.yes its slow but its very un-likey to cause similar problems

yellow circle areas best done with dremel tool


when you have a block magnetically or dye checked for cracks , and sonic tested for bore wall thickness, don,t forget to check lifter bores, and lifter gallery areas, and main cap webs etc. just because its not easy to access does not mean cracks can be ignored




[size=150]these AIR COMPRESSOR POWERED extended reach, die grinders, from harbor freight , (PICTURE BELOW_) are cheap throw away designs, but cheap enough that you can easily buy several, use them until they become unserviceable , then you simply pitch them in the dumpster and grab a new one.
Ive purchased several each time I visit HF. as they come in very handy, these are cheap throw away tools but like shop rags they are very useful ... 25798cb939

Image ... 99698.html

interesting info from ARP



Other Stresses

It must be realized that the direct reciprocating load is not the only source of stresses in bolts. A secondary effect arises because of the flexibility of the journal end of the connecting rod. The reciprocating load causes bending deformation of the bolted joint (yes, even steel deforms under load). This deformation causes bending stresses in the bolt as well as in the rod itself. These bending stresses fluctuate from zero to their maximum level during each revolution of the crankshaft.

Fastener Load

The first step in the process of designing a connecting rod bolt is to determine the load that it must carry. This is accomplished by calculating the dynamic force caused by the oscillating piston and connecting rod. This force is determined from the classical concept that force equals mass times acceleration. The mass includes the mass of the piston plus a portion of the mass of the rod. This mass undergoes oscillating motion as the crankshaft rotates. The resulting acceleration, which is at its maximum value when the piston is at top dead center and bottom dead center, is proportional to the stroke and the square of the engine speed. The oscillating force is sometimes called the reciprocating weight. Its numerical value is proportional to:
It is seen that the design load, the reciprocating weight, depends on the square of the RPM speed. This means that if the speed is doubled, for example, the design load is increased by a factor of 4. This relationship is shown graphically below for one particular rod and piston

I did a quick DOUBLE TAKE on that bottom graph the first time also....look closer at the edges of the graph, its points out the STRONGER the material USED the SMALLER the dia. necessary for a given tensile strength, your limited in clearance on rod bolt max size so the material needs to have higher yeild strength, and potential durrability, to increase the rod bolt strength


"Metallurgy for the Non-Engineer

By Russell Sherman, PE

1. What is grain size and how important is it?

Metals freeze from the liquid state during melting from many origins (called allotropic) and each one of these origins grows until it bumps into another during freezing. Each of these is a grain and in castings, they are fairly large. Grains can be refined (made smaller); therefore, many more of them can occupy the same space, by first cold working and then by recrystallizing at high temperature. Alloy steels, like chrome moly, do not need any cold work; to do this – reheat treatment will refine the grain size. But austenitic steels and aluminum require cold work first. Grain size is very important for mechanical properties. High temperature creep properties are enhanced by large grains but good toughness and fatigue require fine grain size-the finer the better. (High temp creep occurs at elevated temperature and depending on material and load could be as much as .001 per inch/per hour.) All ARP bolts and studs are fine grain – usually ASTM 8 or finer. With 10 being the finest.

2. How do you get toughness vs. brittleness?

With steels, as the strength goes up, the toughness decreases. At too high a strength, the metal tends to be brittle. And threads accentuate the brittleness. A tool steel which can be heat-treated to 350,000 psi, would be a disaster as a bolt because of the threads."

if your worring about the connecting rods,
the 5.7 are the easiest to use and generally provide decent clearance, the 6" require the piston pin be located up into the lower oil ring and whiles its do-able its not ideal.
the 6" in theory provides a couple extra high rpm horse power if the correct cam and headers are used, to maximize the high rpm cylinder scavenging, due to its longer dwell time near TDC and the piston can be made shorter and lighter in weight, and theres a very slight reduction in friction, but in the real world the rod length, is a flip of the coin decision, but ID suggest you use aftermarket 4340 forged rods with 7/16" ARP rod bolts in either case,and spend a good deal of time thinking thru your valve train clearances, and geometry, and lube system as its the rod bolt strenght, or a valve train control issue, or lack of pressurized and cooling oil flow thats the critical factor in many engine failures

read these

Re: tips on building a 383 sbc stroker

PostPosted: October 9th, 2008, 10:48 am
by grumpyvette
"are all rod stretch gauges are NOT created equal "

obviously no more than all girls are equally good looking
but most of the gauges are functional, some just have more features or more precise calibrations, some are adjustable in length ,over a wider range, some have digital read outs, ETC.


BTW I only learned to start checking things carefully after screwing things up just like most of you gentlemen, IM certainly not immune to screw ups, but I DO TAKE NOTES AND TRY NOT TO REPEAT MISTAKES
yes it tends to take a little more effort to do things correctly, sometimes some research, sometimes new tools, are needed, but you may be surprised at the satisfaction you get from knowing its been done correctly

All the little tweaks, and improvements that take you time ,
like port matching
port and bowl clean up
back cutting valves, narrowing valve guides
verifying valve train geometry and clearances
correctly jetting a carb
adding long tube headers
use of an (X) pipe and low restriction exhaust
verifying and correcting the ignition advance curve
correctly gaping and indexing spark plugs
using low resistance ignition wire
correctly setting ignition timing
using the correct t-stat
using a baffled oil pan and windage tray
using roller rockers
porting intake plenum and runner entrances
using thermal piston coatings
using low drag rings
grooving lifter bores
getting the quench distance correct
adjusting the valves correctly
tear drop crank oil feed holes
setting the oil pump pick-up and pump up correctly
adding oil flow too bearings
adding oil coolers

and a couple dozen other mods all individually rarely make a noticeable seat of the pants improvement, but when all done the result is very noticeable in both power and durability



Re: tips on building a 383 sbc stroker

PostPosted: July 13th, 2009, 2:38 pm
by Lester
Hey Grumpy,
I followed your link to this great forum from Digital Corvettes. I am very tempted to build a 383 but need plenty of advise to get the project underway. I tried to read the foll version of this tech article but alot of the links to suppliers and info are no longer available, is there a newer up to date version available?

My story goes something along the lines of a planned new top end at the end of this year, however afer driving quite hard my 77 L82 developed a light knocking noise. Long and short of it is that the no 8 big end failed and has scored the crank. The crank is grindable (suspect 11thou would remove all scoring) but it seems that while it is all apart it might be good time to upgrade. The worstly worn bore at the worst point is worn to 4.011". All rods appear good as do ring seats with only minor wear.

I am on a tight budget as al of this was unplanned, but at the same time only want to do the bottom end once. Being in the UK its difficult to source parts and get the right advise, I also cannot afford to order incorrect parts due to shipping, import taxes, etc. Would you be willing to give me some advise?

Last question, if I were to build a 383 bottom end, along with a suitable cam, etc could I as a temporary measure (about a year) use the original cast L82 heads? I know this is not ideal and would sacrafice alot of power, but I would rather spend the money doing the bottom end right and split the cost than buy the heads and cut costs else where.

Thanks in advance,

Re: tips on building a 383 sbc stroker

PostPosted: July 13th, 2009, 4:24 pm
by grumpyvette
you can certainly re-use the stock heads, IF THEY ARE IN GOOD SHAPE on a 383 short block assembly as a temporary measure
(yes those heads will be a big power restriction, but its only temporary correct?)
most of us in this hobby are on tight budgets and I know EXACTLY how you feel.
you can have a local machine shop bore the current block and install a 3.75" stroker crank and 4.030" pistons to build a 383. reuse of
your stock rods won,t save you any money, as new rods cost less than rebuilding old rods and having them re- sized and ARP rod bolts installed.
but get an INTERNALLY BALANCED rotating assembly with ARP rod bolts , clearance for a stroker as that will allow you to re-use the damper and flex plate , or flywheel you currently have and significantly upgrade the strength. and clear the cam in most cases,
a scat kit with a 9000 series crank would be fine for most applications,

you did not mention the transmission to be used, rear gear ratio, or car weight etc, but once you get the basic short block built you'll need to match the cam selection to those

heres some suppliers to discuss that with ... k_2009.pdf

forged components are generally stronger
(IE will take abuse longer and at greater stress levels) and forged pistons are slightly more heat resistant than hypereutectic or cast
as a general rule if your going to exceed 100hp shot of nitrous or have the rotating assembly spin at near 4000 feet per minute in piston speed forged components tend to be a good investment




alot of your choices will be based on your skills, tools, and budget, but you better do your research carefully, many choices will depend on how durable the parts selected are and if youll use a carb. or efi and limitations like if its got a stock stall converter and an auto trans or a manual trans and the rear gear ratio.
I can easily give you a proven list of parts that will get you 400 plus hp from a 383 sbc but you might not find the combo as street friendly or compatible, with your driving style, or with your current drive train gearing.
keep in mind 400 flywheel hp is different than 400 hp at the pavement and that the heads, cam and compression ratio you select need to be matched to the rpm range and drive train gearing for a combo to function correctly

now alot of guys instantly start pushing VORTEC heads as a cheap option, and in some cases thats a valid choice, but without thinking thru the total package and its intended power range that might be a BAD choice, limiting your potential.
THE smart option is to build a SECOND performance engine , on an engine stand in your garage or Ive even seen it done in a utility room,slowly and carefully built, using decent cost effective components while you drive your current car, and once the second engines complete, and had a test run, you take some weekend and swap engines, thus the original engine is your spare so if you screw up you've got a fall back position and in a single weekend you can be driving a basically stock , dependable transportation option should your dream engine fail or need work, and youll have a great deal less down time waiting on machine shops and parts deliveries

a reasonable limit on cast pistons usually falls near 4000 feet per minute in piston speeds
so your stroke is a factor not just rpms

a balanced set of quality forged pistons can probably handle 4500fpm, or a bit more

Re: tips on building a 383 sbc stroker

PostPosted: July 14th, 2009, 2:07 pm
by Lester
To save filling this thread with info specific to my car I will post a new one with all the details, hopefully you can give me some advise to get the ball rolling.

Re: tips on building a 383 sbc stroker

PostPosted: February 2nd, 2010, 11:45 pm
by grumpyvette
your basic 383 short block can be built on a tight budget, but read thru these links,and sub links for info and tips ... index.html ... t-kit.aspx ... index.html










383 Stroker FAQ from
The 383 chevy is one of the most powerful engines you can build. It is also the source of many questions and a lot of confusion. This is a basic 383 information page. The info is specifically about the properties and special conditions they may require in there buildups.

What is a 383 and what do I need to build one?
A 383 is a 350 production block with a 400 production crank. The crank has some special machine work done, namely the main journals of the 400 are 2.65" and the 350's are 2.45" so they must be turned down by .200" to make the STD. 350 main bearing size. Since the 400 is externally balanced you will need a balancer and flywheel/flexplate for a 400 CID chevy motor.

Do I need special pistons?
Yes and no. The added stroke of the engine would push the piston out of the bore by .125" if you used stock 350 pistons and rods. If you run stock 350 pistons and 400 style rods you can get away without special pistons but The skirts may also hit the counterweights since the 400 crank has larger weights and is longer from the centerline outward. If you go this route you need to pay close attention to crank to piston skirt clearance.

What's with this rod thing?
The 400 uses a 5.56" long connecting rod. All other small block chevy's use a 5.7" rod. The reason for the shorter rod is GM decided not to raise the piston pin higher so they shorted the rod the appropriate length to prevent the piston from popping out. 383's can have many different rod lengths but the first ones used stock 400 rods and stock 350 pistons with relieved skirts before custom pistons were available.

Which rod is better and why?
The longer rods are better than shorter ones. For a full explanation see the rod FAQ
if you wonder why I suggest using SCAT (H) beam style cap screw connecting rods vs stock or most (I) beam designs this picture should show the increased cam to connecting rod clearance

Will longer rods cost more or require special work?
Yes and Yes!! The longer rods themselves don't cost more but the pistons you need will raise in price. The pistons will have higher piston pin heights and will have rings higher up on the piston. In cases where a non stock rod of 6.00" or longer the pin will actually intersect with the oil ring. These will require support rails for the ring. The longer rods will also make cam to rod clearance an issue. Special grinding or clearancing of the rod bolt shoulder will be required and/or a reduced base circle camshaft will be required.

What will the block require?
The block will need to be notched in the oil pan area. The longer stroke crank will need deeper notches to clear the counter weights and rod throws.

Should I balance the motor?
Yes!!!!! Any time you change geometry from stock a balance job is neccessary. That is if you want it to live! The pistons and rods are lighter than stock 400 versions and there is too much counterweight. This will make for a lot of vibrations and that is bad for a motor.

What kind of heads do I need?
Any kind you want. A 383 takes the same cylinder heads as a 350. The 383 does like larger heads and big valves but it is not mandatory to have 2.02/1.60 valves and huge intake runners.

Do I need steam holes in these heads?
No! A 383 uses a 350 block and it has no provisions for steam holes. It also cools like a 350 so only minor cooling system upgrades are neccessary.

What is the cost of this kind of buildup?
This is a tricky question and probably the most asked one! A 383 can be very pricey. The crank will cost a pretty penny to find a used one. There are several aftermarket companies selling '383' cranks that don't require any work so said. A crank can cost anywhere from 250 to over 1800$ depending on the kind and quality of the crank you buy. Pistons also fall into this wildly ranging category. You can spend 150 on cheap cast pistons or over 500 on light forged units. The balance job can cost from 120 to 240 depending on the shop, kind of balance job and the area you live in. Block work is not too bad. The only extra is the notching and that can be from 100-175 for the work. The rods are also another area of wide variety. You can get stock reworked 400 rods with ARP bolts for 100$ and you can order the 700$ sportsman rods and so on. If you order aftermarket rods that are profiled for stroker motors you will save yourself the grinding of the rods and/or the reduced base circle cam. If you get stock rods or non profiled rods you will either have to grind them yourself or pay your shop 50-100$ for this. You will also need to do this before the motor is balanced!!! I have built them for around 1600 and as much as 10,000 so far so do some leg work and pricing!

How much power will the stock 400 crank handle?
I have used a prepped 400 crank to 700+HP I have used basically stock cranks to over 550 HP so a stock nodular iron crank is fine for most buildups. The crank is strong because of the beefier construction of the crank.

What is the red line on these motors?
The red line varies from motor to motor depending on the parts installed and work done etc... A basic short rod 383 will live to 5500 and a 5.7" rod motor will go to 6500. Motors with forged internals and special work done can of course go higher. As a basic rule of thumb you can go 1000 RPM per 10PSI of oil pressure. If you have 70 PSI you can make 6000 with a 10 PSI safety margin. This rule will affect every kind of motor. It's kinda of an either/or here. You can go as high as your oil pressure permits or the internal parts permit whichever is lower!

What size cam will I need?
Probably the second most asked question is cam sizing. This is another tricky thing to pick. Since every single aspect of the engine and vehicle it's installed in will affect this I will just give another rule of thumb. 99% of rated ranges on products are based on the 350. If you have built a 383 you can add 10 degrees of duration to the motor and get very similar characteristics. For example; A 350 would probably have a moderate to rough idle with a 224 duration cam, measured @ .050 lift. The 383 will take a 234 duration cam to make almost the same idle and vacuum as the 350. These motors also like to breath so longer duration larger lift cams work well in them. Don't overcam! Just because you have a bigger engine don't go stuff the largest cam you can find into it. Most street engines use less than 234 degrees of duration @ .050! The motor is bigger so it will make more power with less cam so a 383 with a 214 cam will make more power than a 220 duration cam 350 if all else was the same.

What intake and manifold should I use?
Intake should be a high rise aluminum and a moderate carb. The 383 likes to breath so a bigger intake manifold like the RPM or Stealth would be a better choice but the performer and action + manifolds will work. Carb also depends on application but on the street under 6000 RPM you could get away with a 650! A 750 would make more power but is the largest you should go unless you are all out racing!

Are there any special things I need to pay attention to when assembling the motor?
Yes you must check cam to rod clearance and block to rod clearance. Both should be .050" minimum! All other specs will be the same as a 350 or whatever the manufacture specifies.

Should I run a high volume oil pump?
Only if you have a deep extra capacity oil pan. I personally do not like or condone high volume oil pumps on any engine. A stock oil pan will be sucked dry by a high volume pump @ 4500 RPM under hard acceleration. I have rebuilt more than a few motors that burnt up this way.

Re: tips on building a 383 sbc stroker

PostPosted: December 20th, 2010, 4:51 pm
by grumpyvette
I am a newbie and have a few questions about a motor I am thinking about buying for my 62 Impala. It currently has a stock 283 and stock tranny, but was thinking about upgrading to a 383 with the following specs... Could you let me know what you think about the following for $1600

Hypereutectic pistons Pistons
Chromoly Rings
Connecting Rods (shot peened & reconditioned)
Clevite Rods and Main Bearings
New EagleCrankshaft
New Head Bolts
Comp Cams Flat Tappet Hydraulic Camshaft (Your choice)
Flat Tappet Hydraulic Lifters
Double Roller Timing Chain
Brass Freeze Plugs
4 Bolt Mains
010 High Nickle Block

Block Machine Work
Hot Tanked
Shot Peened

Honed with Torque Plates

Head Parts
1.94/1.50 Stainless Steel Swirled Valves
Valve Seals
Comp Cams Valve Springs
Hardened Seats
Head Machine Work
Hot Tanked
Shot Peened
5 Angle Value Job
(no intake, carb, oil pan, valve covers, damper, flexplate, exhaust, water pump, distributor).


can you post a link to the add and supplier info?

what your listing as parts is basically a standard rebuild using common refurbished components and not an engine most performance oriented people will be happy with and its not likely to be a good base to work from,
if its an ADVERTISED engine from lets say EBAY or a builder without a strong national reputation ID be EXTREMELY hesitant at spend money on an engine with that description, rather than buying a G.M. crate engine or from a WELL KNOWN national builder
there a strong tendency to shop with LOW total price being the main factor, in deciding where the best deals are but the truth is that, many of the cheaper engines are basically cheap slap together combos with darn little if any guarantee or thought to the combos durability or power.
I constantly see guys buying engines where the PRICE was the main selling point who get varying levels of CRAP for their money

youll more than likely be well ahead buying a NEW G.M. 350 4 bolt block CRATE ENGINE, with a warranty ... 9/10002/-1

or if your determined to build a 383 sbc , theres other options ... 0/10002/-1 ... 1/10002/-1

its better to spend a bit more and get a known good basic engine than waste $1600 PLUS on unknown recondition or used junk of unknown condition

Re: tips on building a 383 sbc stroker

PostPosted: April 23rd, 2012, 8:59 am
by grumpyvette
"hey GRUMPY? I just assembled my first 383 small block for my 1965 chevelle,and on start-up it had a noticeable ticking or light knocking I stopped the cam break-in and pulled it back apart but can,t find a darn thing wrong, the bearings look great, any ideas?"

IF its a 383 you built from a 350 the most common sources for knocking sounds on a new engine if you've checked everything during the assembly process,are either valve train or exhaust leak related, but loose stall converters clutches flex-plates and bell housings and drive shaft u-joints are highly suspect.are the rods just touching the oil pan flange area, the rods touching some cam lobes, the pistons hitting the heads, valve spring bind, push-rods rubbing the guides or cylinder head slots,the rockers binding on the rocker studs or valve spring retainers, a bad rocker or other valve train related component binding,or failure to have .060 minimum block to rod clearances, if theres noise theres a wear indication someplace where some parts touching, somethings not clearanced correctly.
obviously that assumes you have good oil pressure and oil flow, you've verified valve train clearances and adjusted the valves correctly and installed and degreed in the cam correctly, and clearanced the rotating asembly
read the links for more ideas












Re: tips on building a 383 sbc stroker

PostPosted: May 28th, 2012, 10:38 am
by grumpyvette
" so what would you build grumpy, if you had a limited budget and wanted a 383 for your 1970 nova or camaro?
its got a muncie 4 speed and a 3.90:1 rear gear and a mild 350 now"

well obviously Id need to know the budget were dealing with and the skill level of the person doing the work, and if the car needs to pass emission testing., any and all other factors you can post will help,
without knowing the crank stroke, compression ratio rod length, type of rod bolt, piston weight and several other factor like balance tolerance , quench, valve train,components used and clearances, you can only make rough guess,as too the durability limitations due to both lubrication and component stress, things like valve spring load rates sand the strength of rod bolts do have a marked effect on any builds rpm limitations, you can calculate the theoretical limitations ,but these dozens of factors that must be used. Id suggest staying UNDER 4000FPM in piston speed even with a forged crank when using 3/8" rod that doesn,t mean the engine will instantly self destruct if you push a bit past that but its darn sure going to be adding significantly more stress, and stress IS CUMULATIVE.
Any hydraulic valve train is going to start at least potentially be nearing its stability limitations by about 6000rpm if stock or nearly stock components are selected, swapping to a solid lifter valve train tends to extend the rpm potential, but again component selection and care taken during assembly have a big effect on results.

4000 fpm with a 3.75" stroke thats approximately 6400rpm

with a 3.00 stroke like on a 302 thats almost 8000rpm

READ THese threads and sub-links



your manual transmission and rear gear ratio make this potentially a good performance build, but most of us are limited to a rather small budget and a need to drive the car as daily transportation and run on easily available pump octane fuel, so you have to think things thru,

heres a few links to help, you get some ideas











Re: tips on building a 383 sbc stroker

PostPosted: February 9th, 2014, 10:29 am
by grumpyvette

модная одежда и обувь

PostPosted: March 4th, 2016, 7:20 am
by Thomasot