and theres that P.I.T.A. FACT that building an engine to produce impressive PEAK POWER, you can brag about to your buddies almost always results in an engine with less than ideal street drive-ability, especially if you want good gas mileage or like to cruise at 2000rpm
every choice you make is a compromise in some area, if you want massive low and mid rpm torque and instant re responsiveness, in your engine your very likely to be trading those characteristics at the expense of high peak horse power, if you want bragging rights and impressive power your very likely to pay a price in less than ideal manors in traffic and loss of low rpm power , theres EASILY A POTENTIAL OF 80-120 HORSEPOWER DIFFERENCE IN YOUR SELECTION OF HEADS CAM AND COMPRESSION RATIO ALONE
you would be foolish to ignore the available info, in these links
http://www.camquest.com/
viewtopic.php?f=52&t=399
http://www.strokerengine.com/SBCHeadsFlow.html
viewtopic.php?f=52&t=10947&p=48126#p48126
viewtopic.php?f=52&t=181
search.php?search_id=active_topics
viewtopic.php?f=52&t=3802
viewtopic.php?f=69&t=8540
viewtopic.php?f=52&t=1070
viewtopic.php?f=50&t=9250&p=33361#p33361
viewtopic.php?f=52&t=8582
viewtopic.php?f=52&t=10947&p=48126#p48126
viewtopic.php?f=44&t=38
viewtopic.php?f=52&t=401
viewtopic.php?f=52&t=82
viewtopic.php?f=69&t=8540
viewtopic.php?f=71&t=741&p=1048#p1048
viewtopic.php?f=52&t=266&p=40004&hilit=+best+vortec+heads#p40004
http://www.technovelocity.com/chevyhack ... cation.htm
viewtopic.php?f=50&t=9040&p=38048&hilit=ford+nine+inch#p38048
http://www.chevyhiperformance.com/techa ... ine_build/
viewtopic.php?f=50&t=10363
viewtopic.php?f=50&t=46&p=55&hilit=+books+video#p55
if your building a sbc street/strip engine every component works a part of a total system, your always restricted by the weakest link in the chain, or the biggest restriction, and with engines its air flow rates, fuel/air ratios,cylinder scavenging,ignition advance curve and compression that determine a great deal of your potential power.
REMEMBER A MANUAL TRANSMISSION ALLOWS YOU A GREAT DEAL MORE FLEXIBILITY IN CAM SELECTION
keep in mind you need to think thru the combo as a package where all parts selected must complement each other and be designed to operate in approximately the same basic rpm band and flow and effectively burn and use the pressure generated from similar amounts of fuel/air mix.
one very common mistake is selecting a cam duration,that exceeds or limits the engines rpm band, a rear gear ratio,thats not matched to the intended power band,or selecting a compression ratio or set of heads that can,t operate with the other components in the same power band efficiently
the best heads matched to a restrictive intake or the wrong cam will result in a DOG just as surely as a great intake and crappy heads with low compression, or any of a few dozen other miss-matched parts.
READ THIS LINKED INFO
viewtopic.php?f=69&t=9930
Change Cam - Gain 78 HP ..... "article on page 22, in the magazine" [Best of Tech /Winter 2003]
A few years ago there were claims by a magazine of adding 78 horsepower to a wimpy 8.6:1 compression-ed 355 sbc equipped w/"the usual hot rodding parts" headers, 750 Speed Demon carb, Edelbrock Performer RPM Air-Gap intake, 2.02/1.60 Summit aluminum heads, MSD, ect.
Just using an Erson TQ40 cam kit [218/228@.050 duration][.472 valve lift, w/1.5:1 rockers]
instead of the stock small block Chevy [195/202 duration] factory type [.390/.410 lift] camshaft ...
Using this Erson TQ40 cam, it showed gaining a maximum of 78 hp @ 5,600 RPM = [403 hp/maximum] .....
and gaining 20 pounds of torque, @ 4,400 RPM = [418# torque/maximum] over the stock low lift camshaft.
Oddly enough, from 2,000-to-3,900 RPM, results were [-1 horsepower] and [-4 pounds of torque].
Average gains from 2,000-to-5,900 RPM, were 44 horsepower & 35 pounds of torque .....
This Erson TQ40 cam showed gaining 78 hp & 78 pounds of torque, from about 4,000-to-5,900 RPM.
now 78 hp gain looks impressive but if you retained the stock rear gear and converter youll spend very little time in the 4000rpm-6000rpm power band so a cam like that won,t produce nearly the gains, in performance you might expect without making the matching drive train mods so the engine operates mostly in the new higher average power band, it makes little difference if your engine makes 100 more hp if it makes it only in an rpm band you seldom reach or use!.
if you want the car to run decent you need to significantly increase the air flow rates,and feed the required fuel to maintain the correct f/a ratio and that requires much better flowing heads,much better flowing intake and a cam with more lift and duration and a higher stall speed converter and a 3.54:1-or- 3.73:1 rear gear ratio
a cam that will move the intended power range high enough to make that intended power curve is required , but planing where in the rpm range that power curve is strongest is your first decision,..... all the components selected must match,that intended power curve, and the cam, compression ratio and head flow need to match that combos goal, you can build a good street combo with massive torque in the rpm range you normally drive, (usually 1800rpm-4500rpm, on most street cars) for use on the street or you can build a race engine with far better peak power (up in the (4500rpm-6500rpm range) but it won,t be nearly as much fun to drive at low rpms or on the street, in fact its only going to work great on a dyno or where you can drive while keeping the engine rpms in the 4500-6500 range in most cases
keep in mind if your gearing keeps the engine rpms in the 1500rpm-5500rpm range and the transmission shifts at 5500rpm under wide open throttle like most nearly stock engines do its rather useless to cam the engine or use heads designed to maximize power in the 5500-700rpm range
put your info into this program, don,t exaggerate or lie, just input what you really have top work with
http://www.camquest.com/
a typical sbc makes about 1.1 ft lb of torque per cubic inch of displacement
your torque curve depends mostly on your engines displacement,compression,head, & intake flow and cam timing
the formula for hp is torque times rpm divided by 5252=hp
a higher torque peak generally increases power

this is a very typical dyno chart from an engine with stock heads a mild cam and stock exhaust and intake, as all components are designed for max low and mid rpm torque, you can easily move the peak hp and torque number higher , with larger head ports cam duration, better intake and less restrictive headers and exhaust but doing so tends to reduce the off idle responsiveness and torque, as every choice is a compromise in some area.
example
400 ft lbs at 3500rpm=267hp
400 ft lbs at 5500rpm=419hp
400 ft lbs at 6500rpm=495hp
you'll want to run about 10:1 cpr on the street to maximize performance, because on pump gas thats about the max you can use, but the cam selected effects the dynamic compression ratio so you can use a bit more compression with a longer duration cam and a bit less with a lower duration,
heads that flow about 250cfm or more at .500 lift are going to be a huge asset, but the port cross sectional area will tend to vary based on where you want peak hp,
if your going for an aggressive combo a bit more on the race end of the scale but a compromise to keep it semi-street-able, you'll usually need a 3.54:1-3.73:1 rear gear and a manual transmission or a 2700rpm-3000rpm stall converter to maximize acceleration, with a cam that's designed to maximize power in the 3000rpm-6300rpm band
personally if I was building as hot street combo, Id select a complete rotating assembly with matched components,from a single supplier, it will tend to avoid problems or finger pointing if parts don,t match and fit, specifically say you want those components and balanced, a good scat cast STEEL 9000 balanced crank and 5.7" connecting rods with 7/16" rod bolts,and forged pistons, do the research and make sure you get match and balanced parts
If it was a street and race combo ID also specify INTERNAL BALANCE and 4340 forged rotating parts
YOU CAN LEARN A GREAT DEAL, ABOUT COMBOS THAT WORK, IF YOU READ THRU ALL THE LINKS AND SUB LINKED INFO BELOW, YES IM FULLY AWARE IT WILL TAKE SOME EFFORT AND TIME, IT WILL ALSO SAVE YOU WEEKS OF WASTED EFFORT AND HUNDREDS OF DOLLARS
BTW I JUST TOOK THE TIME TO RE_READ THIS THREAD< ITS A VIRTUAL CLASS IN ENGINE ASSEMBLY THAT SHOULD BE READ BY EVERY LAST MEMBER

http://www.themotorbookstore.com/resmchstvi.html
[b]this is exceptionally useful for newer guys[/b]
http://www.hioutput.com/tech/343hp/343hp.html
(if your stuck using restrictive heads, follow this build and use much of what can be used as its designed to maximize restrictive heads)
keep in mind you have a great deal of options,in parts that can be used,and your selection will have a huge effect on where in the rpm range you make the best power, and making 1.1-up to-1.4 horsepower per cubic inch is not that difficult, with the correct parts.
if you read thru the links and sub links youll find many tips and combos
viewtopic.php?f=69&t=3814&p=18361#p18361
viewtopic.php?f=69&t=519
viewtopic.php?f=52&t=727
http://www.hotrod.com/techarticles/383c ... ock_build/
viewtopic.php?f=50&t=3156&p=8424#p8424
viewtopic.php?f=52&t=266&p=322&hilit=215cc+vortec#p322
viewtopic.php?f=52&t=1070
viewtopic.php?f=53&t=8310&p=28891#p28891
viewtopic.php?f=32&t=3525
viewtopic.php?f=52&t=148&p=182#p182
http://www.airflowresearch.com/articles ... 5/A-P1.htm
http://www.strokerengine.com/SBCHeadsFlow.html
viewtopic.php?f=44&t=38
viewtopic.php?f=55&t=8485
viewtopic.php?f=87&t=3404&p=8992&hilit=2800+3200+power+weight#p8992
http://www.airflowresearch.com/articles ... 1/A-P1.htm
http://www.airflowresearch.com/articles ... A16-P1.htm
viewtopic.php?f=44&t=38
viewtopic.php?f=56&t=495
viewtopic.php?f=44&t=38&p=26432&hilit=+known+engine+combo#p26432
viewtopic.php?f=52&t=975&p=1700&hilit=210cc#p1700
viewtopic.php?f=52&t=5537&p=16744#p16744
viewtopic.php?f=50&t=6624
viewtopic.php?f=32&t=5521&p=16619#p16619
http://www.circletrack.com/tipstricks/4 ... index.html
viewtopic.php?f=69&t=5357&p=16030#p16030
viewtopic.php?f=50&t=111
viewtopic.php?f=52&t=10705
viewtopic.php?f=32&t=3525
viewtopic.php?f=52&t=5364
http://airflowresearch.com/articles/article115/A-P1.htm
http://airflowresearch.com/articles/art ... A27-P1.htm
http://airflowresearch.com/articles/article085/A-P1.htm
http://vexer.com/automotive-tools/1-4-m ... calculator
viewtopic.php?f=50&t=1249
viewtopic.php?f=52&t=5364&p=16066#p16066
example
here posted below are two 383s on dyno software with different heads cams and intakes almost everything else is similar,
look at the differences in torque and peak hp that the changes made in
BOTH the low range (1500rpm-4500rpm) (noticeably more low rpm torque)
and the upper or peak hp, (4500rpm-6500rpm) (a good deal more peak hp)
KEEP IN MIND THE STOCK AUTOMATIC TRANSMISSIONS GOING TO SHIFT AT ABOUT 5000RPM OR LOWER,AND STOCK REAR GEARS ARE EFFECTIVELY PREVENTING YOU FROM USING THE WILDER CAMS POWER IF THE DRIVE TRAIN IS NOT MODIFIED TO FUNCTION IN THAT HIGHER RPM BAND, REMEMBER SELECTING COMPONENTS TO MATCH THE INTENDED POWER BAND IS CRITICAL


heres a chart I found that I don,t fully agree with, I think its a bit conservative, by about 3%-5% on the required cam duration ,required to avoid detonation with todays crappy octane fuel, but it at least gives you a base to work from, but Id suggest selecting a bit more duration
why not call crane,
1-866-388-5120
crower,1-619.661.6477
erson,1-800-641-7920
lunati 1-662-892-1500
and
isky 323.770.0930
and talk to the tec support guys about what they suggest but DON,T mention anything any other cam manufacturer suggests during the conversations, just present the info on the parts used in that combo, rear gear ratio, compression, etc and see what they suggest, then make up your mind.

190cc heads tpi, mild cam (crane 119561)

Volumetric Efficiency: Is calculated by dividing the mass of air inducted into the cylinder between IVO and IVC divided by the mass of air that would fill the cylinder at atmospheric pressure (with the piston at BDC). Typical values range from 0.6 to 1.2, or 60% to 120%. Peak torque always occurs at the engine speed that produced the highest volumetric efficiency.
keep in mind as rpms increase so do port speeds and volumetric efficiency UP TO A POINT, WHERE THE TIME LIMITATION TO FILL AND SCAVENGE the cylinder limits power

210cc heads single plane intake wilder cam (CRANE 119601)
if your building a 383 sbc these links and sub links will help
SAFE piston speeds are best restricted to 4000fpm for stock components and 4500fpm for the better common aftermarket components
read these threads
viewtopic.php?f=52&t=2627&p=6780&hilit=ramp+rate+lobe#p6780
viewtopic.php?f=52&t=788&p=10777&hilit=cast+cores#p10777
viewtopic.php?f=52&t=181&p=9294&hilit=cast+cores#p9294
viewtopic.php?f=52&t=5078
viewtopic.php?f=53&t=343&p=16772&hilit=redline#p16772
viewtopic.php?f=53&t=341
viewtopic.php?f=50&t=1249&p=7598&hilit=stroker+tips#p7598
viewtopic.php?f=50&t=428&p=7304&hilit=stroker+tips#p7304
viewtopic.php?f=44&t=38&p=46#p46
http://www.trickflow.com/articles/dynod ... _heads.asp
viewtopic.php?f=32&t=3525
http://www.brodix.com/heads/tonydyno.html
http://airflowresearch.com/articles/article085/A-P1.htm
http://airflowresearch.com/articles/article031/A-P1.htm
http://airflowresearch.com/articles/article096/A-P1.htm
viewtopic.php?f=50&t=3156&p=18989&hilit=6.385+inch+rods#p18989
IF your building a stroker big block,combo,you might find info here in the thread below and its sub links useful
keep in mind the 383 small block has become almost the standard its basically the 350 with a 1/4" stroker crank and a slight .030 over bore,to clean up and wear in the 350s bore
in the similar manor a 454 big block with a .030--.060 over bore and a 1/4" stroker crank assembly is used to build a 489-496 big block version
viewtopic.php?f=44&t=5531