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383 build

PostPosted: December 22nd, 2009, 9:05 am
by rumrumm
My goal with this combination was to have a powerful engine with good street manners for my street rod, something that not only had show but go as well. So I settled on a 383 with the following combination of parts:

Eagle SIR 6.0 inch connecting rods
Eagle cast steel crankshaft
SRP forged flat top pistons
CompCams 280 Magnum flat tappet hydraulic cam (230/230 duration @.050, 480/480 lift)
AFR 190 heads (68cc chambers)
CompCams ProMagnum roller rocker arm (1.52)
Edelbrock RPM intake manifold
Edelbrock 750 carb
MSD Pro Billet distributor with MSD wires

This combination resulted in a static compression of 10.6:1 and a dynamic compression ratio of 8.46. I have never had any problems running 92-93 octane pump gas. The best dyno run was made with total timing set at 32 degrees. I think this is a good example of how good breathing heads can make excellent power even with a street-friendly cam. See below:

BAND Ft-Lbs CHP #/HrHP Deg F Deg F 100 % #/Hr SEC
3148 432.5 264.7 0.532 75.0 186 1.071 92.0 127.4 1.9
3200 441.5 268.7 0.521 75.0 186 1.071 92.0 126.8 16.9
3300 439.4 275.9 0.502 74.5 187 1.071 92.0 125.3 7.3
3400 435.3 282.0 0.485 74.5 187 1.071 92.0 123.7 3.5
3500 437.4 291.2 0.474 74.5 187 1.071 92.0 125.0 3.4
3600 438.4 300.4 0.463 74.5 187 1.071 92.0 125.8 3.3
3700 440.4 310.6 0.453 74.5 187 1.071 92.0 127.0 1.6
3800 443.6 320.9 0.440 74.5 187 1.071 92.0 127.7 3.2
3900 446.6 332.1 0.428 74.5 187 1.071 92.0 128.3 1.5

4000 455.1 346.4 0.409 74.5 187 1.071 92.0 127.9 1.5
4100 462.9 360.7 0.468 74.5 188 1.071 92.0 135.7 1.5
4200 463.1 376.0 0.418 74.5 188 1.071 92.0 141.9 1.4
4300 467.7 387.3 0.422 75.0 188 1.071 92.0 147.9 1.4
4400 467.0 395.5 0.430 74.5 188 1.071 92.0 153.8 2.7
4500 466.1 403.6 0.438 74.5 188 1.071 92.0 159.7 2.7
4600 463.0 410.8 0.451 74.5 188 1.071 92.0 167.2 1.3
4700 460.0 419.0 0.464 75.0 188 1.071 92.0 175.1 2.6
4800 459.0 425.1 0.471 74.5 188 1.071 92.0 180.8 3.8
4900 457.9 431.2 0.465 74.5 188 1.071 92.0 180.8 2.4

5000 455.8 434.3 0.468 74.5 188 1.071 91.9 183.2 2.4
5100 449.6 434.3 0.470 74.5 188 1.071 91.9 185.0 3.5
5200 449.6 437.4 0.469 74.5 188 1.071 91.9 186.4 3.5
5300 438.4 442.5 0.473 75.0 188 1.071 91.9 188.5 3.4
5400 431.2 443.5 0.481 74.5 188 1.071 92.0 192.1 2.2
5500 423.1 443.5 0.491 74.5 188 1.071 92.0 195.6 4.4
5600 415.9 444.7 0.496 74.5 188 1.071 92.0 198.0 2.1
5700 412.8 449.8 0.496 75.0 189 1.071 92.0 200.1 1.1
5800 397.5 438.4 0.513 75.0 189 1.071 92.0 202.1 3.1
5900 389.3 437.4 0.520 74.5 189 1.071 92.0 204.1 2.0

6000 378.1 431.3 0.533 74.5 189 1.071 92.0 206.0 1.0
6100 373.0 433.3 0.536 74.5 189 1.071 92.0 208.1 2.0
6162 364.8 428.2 0.546 75.0 189 1.071 92.0 209.3 1.0

Re: 383 build

PostPosted: December 22nd, 2009, 12:08 pm
by grumpyvette
maintaining 430 plus ft lbs of torque from 3100-5400rpm, and having well over 400hp makes that a very nice combo for a street rod

btw heres something to compare it too, look carefully at the components that were used and the resulting power curve ... s&pc_id=21
read this thread and sub links

383 Alum / Forged / Carb

4 bolt main 1pc rear seal block w/Passenger side dipstick only
Square and parallel decked
Align honed main bearing bore
Cylinders honed on computer controlled machine to within .0002 straightness and roundness
Cylinders are sonic tested for thickness
Rotating Assembly:
New SCAT forged crankshaft
New SCAT I-beam rods
New PROBE forged pistons
Hastings Moly rings
Balanced rotating assembly
Melling high volume oil pump
Roller cam
Heavy duty double roller timing set
Comp Cams Pro Magnum roller rockers
Cylinder Heads:
New DART aluminum cylinder heads
1.437 diameter valve springs
Hardened retainers and springs
2.02 swirl polished intake valves
1.60 swirl polished exhaust valves
Hardened push rods
1.6 Ratio Rocker Arms
A Ton Of Extras:
Professional Products dual plane polished aluminum intake manifold
Edelbrock 750 cfm carburetor
MSD distributor and coil
Edelbrock 110GPH fuel pump
Edelbrock polished aluminum water pump
MSD plug wires
AC Delco spark plugs
9.5 to 1 compression
Signature series aluminum valve covers
Brass freeze plugs
Dyno tested – and shipped with results
Comes with 30 month / 50,000 mile warranty


Blueprint Engines recommends 91 Octane for this engine and a 2000-2400 RPM stall converter

Critical Specs:

Rod Length:
.528 Int / .535 Exh & 220 Int / 226 Exh duration @ .050 - 110 degree lobe sep.
Compression Ratio:
9.5 to 1
Ignition Timing:
15 Degrees Initial / 36 Degrees Total

now read thru this thread


I get asked all the time if 6" or 5.7" rods are the best selection for the 383 sbc builds, the truth is both have some advantages and disadvantages, as an example I selected two very similar forged KB pistons to compare with similar compression ratios that might be used in a kick butt racing combo, with 12.5:1 cpr for a weekend warrior style 383 sbc
so lets look at the differences as they will have similar traits to other pistons

heres a link to KB pistons, Ive used dozens of these sets with good results



advantages & disadvantages of the 5.7" rods and pistons, in a 383 sbc

less clearance for the counter weights , to pass under the skirt, higher thrust loads on cylinder walls
higher reciprocating weight
481 grams piston / 132 grams pin
rings fully supported in oil ring groove, as the piston pin is lower
slightly longer and potentially more stable bore skirt contact area

advantages & disadvantages of the 6" rods and pistons, in a 383 sbc
lower reciprocating weight ... s&P_id=391
more clearance for the counter weights , to pass under the skirt, lower thrust loads on cylinder walls


418 grams piston / 132 grams pin
THATS 63 grams lighter than the 5.7" piston
rings not fully supported in oil ring groove, as the pin by-sects the lower oil ring groove
slightly shorter and potentially less stable bore skirt contact area

related info


Tech Tip - 2005

Rod Lengths/Ratios: Much ado about almost nothing.

Why do people change connecting rod lengths or alter their rod length to stroke ratios? I know why, they think they are changing them. They expect to gain (usually based upon the hype of some magazine article or the sales pitch of someone in the parts business) Torque or Horsepower here or there in rather significant "chunks". Well, they will experience some gains and losses here or there in torque and or H.P., but unfortunately these "chunks" everyone talks about are more like "chips".

To hear the hype about running a longer Rod and making more Torque @ low to mid RPM or mid to high RPM (yes, it is, believe it or not actually pitched both ways) you'd think that there must be a tremendous potential for gain, otherwise, why would anyone even bother? Good question. Let's begin with the basics. The manufacture's (Chevy, Ford, Chrysler etc.) employ automotive engineers and designers to do their best (especially today) in creating engine packages that are both powerful and efficient. They of course, must also consider longevity, for what good would come form designing an engine with say 5% more power at a price of one half the life factor? Obviously none. You usually don't get something for nothing - everything usually has its price. For example: I can design a cam with tremendous high RPM/H.P. potential, but it would be silly of me (not to mention the height of arrogance) to criticize the engineer who designed the stock camshaft. For this engine when I know how poorly this cam would perform at the lower operating RPM range in which this engineer was concerned with as his design objective!

Yet, I read of and hear about people who do this all the time with Rod lengths. They actually speak of the automotive engine designer responsible for running "such a short Rod" as a "stupid SOB." Well, folks I am here to tell you that those who spew such garbage should be ashamed of themselves - and not just because the original designer had different design criteria and objectives. I may shock some of you, but in your wildest dreams you are never going to achieve the level of power increase by changing your connecting rod lengths that you would, say in increasing compression ratio, cam duration or cylinder head flow capacity. To illustrate my point, take a look at the chart below. I have illustrated the crank angles and relative piston positions of today's most popular racing engine, the 3.48" stroke small block 350 V8 Chevy in standard 5.7", 6.00", 6.125" and 6.250" long rod lengths in 5 degree increments. Notice the infinitesimal (look it up in the dictionary) change in piston position for a given crank angle with the 4 different length rods. Not much here folks, but "oh, there must be a big difference in piston velocity, right?" Wrong! Again it's a marginal difference (check the source yourself - its performance calculator).

To hear all this hype about rod lengths I'm sure you were prepared for a nice 30, 40, or 50 HP increase, weren't you? Well its more like a 5-7 HP increase at best, and guess what? It comes at a price. The longer the rod, the closer your wrist pin boss will be to your ring lands. In extreme situations, 6.125" & 6.250" lengths for example, both ring and piston life are affected. The rings get a double whammy affect. First, with the pin boss crowding the rings, the normally designed space between the lands must be reduced to accommodate the higher wrist pin boss. Second, the rings wobble more and lose the seal of their fine edge as the piston rocks. A longer Rod influences the piston to dwell a bit longer at TDC than a shorter rod would and conversely, to dwell somewhat less at BDC. This is another area where people often get the information backwards.

In fact, this may surprise you, but I know of a gentleman who runs a 5.5" Rod in a 350 Small Block Chevy who makes more horsepower (we're talking top end here) than he would with a longer rod. Why? Because with a longer dwell time at BDC the short rod will actually allow you a slightly later intake closing point (about 1 or 2 degrees) in terms of crank angle, with the same piston rise in the cylinder. So in terms of the engines sensitivity to "reversion" with the shorter rod lengths you can run about 2-4 degrees more duration (1-2 degrees on both the opening & closing sides) without suffering this adverse affect! So much for the belief that longer rod's always enhance top end power!

Now to the subject of rod to stroke ratios. People are always looking for the "magic number" here - as if like Pythagoras they could possibly discover a mathematical relationship which would secure them a place in history. Rod to stroke ratios are for the most part the naturally occurring result of other engine design criteria. In other-words, much like with ignition timing (spark advance) they are what they are. In regards to the later, the actual number is not as important as finding the right point for a given engine. Why worry for example that a Chrysler "hemi" needs less spark advance that a Chevrolet "wedge" combustion chamber? The number in and of itself is not important and it is much the same with rod to stroke ratios. Unless you want to completely redesign the engine (including your block deck height etc.) leave your rod lengths alone. Let's not forget after all, most of us are not racing at the Indy 500 but rather are hot rodding stock blocks.

Only professional engine builders who have exhausted every other possible avenue of performance should ever consider a rod length change and even they should exercise care so as not to get caught up in the hype.

yeah I know most people won,t read all the sub links that contain a great deal of info, but youll be very surprised at all the info those sub links contain




Re: 383 build

PostPosted: February 22nd, 2010, 3:18 pm
by grumpyvette
IF your interested in building a street monster and have the cylinder heads to support the hp/tq these cams can potentially provide like a brodix IK
200cc or 215cc ... tId=760699

or AFR 210cc head,

or even the DART PLATINUM 200cc-215cc

heads on a 383 sbc, and your willing to use a flat tappet solid lifter cam with less than ideal street manors to save the cost of a roller both these cams require a 3200rpm stall converter or a manual transmission to work to their full potential, and the correct rear gear ratio

slightly milder works great on the street, with 3.73-3.90:1 gears and street tires
wilder works great on the track with slicks and a 4.11-4.33:1 gear(not a good street cam in my opinion)

AS long as you have a minimum of 10.5:1 static cpr,IVE used these flat tappet solid lifter cams in several 383 sbc, matched to a good dual plane intake like the newer AIR STRIKE or RPM air gap intakes, and 1.6:1 roller rockers .
Image 3.73:1-4.11 rear gears and a 750cfm holley or demon carb for years with good results ... 1/A-P1.htm

with the wilder isky cam and a 4.11:1-4.56:1 rear gear, and that isky cam listed above, the single plane intakes like the

become a valid choice, provided your willing to spin the engine into the high 6500rpm plus range going thru the lights, and your tire diam. and gearing keep you in the 4000rpm-6500rpm band most of the time

Re: 383 build

PostPosted: May 19th, 2010, 12:27 pm
by grumpyvette
read these first


you might find these interesting, as a good well proven hot street combo, for a light car with a 4.11-4.56 rear and manual transmission

rotating assembly ... cts_id=675


specs>> 310°/310° 244°/244° .510"/.510" 108°

Ive used this solid lifter flat tappet cam many times with great results in similar 350-383-406 sbc build-ups ... vl=2&prt=5
244°/252° .518"/.536" 112°

both cams produce best results with 1.6:1 roller rockers


don,t forget a good high capacity oil pan, designed to fit your car and decent headers as both will be critical to producing decent hp
compression ratio should be in the 10:1-10.5:1 range, quench in the .038-.044 range ... 1&parent=0