just how restrictive are the stock TPI engine components?

[grumpyvette]

I get this question frequently so let me point out a few things



http://garage.grumpysperformance.co...at-manifold-air-temp-sensor.10349/#post-42530

“While I’m this far….?”

I must have said this to myself daily for the past few months & I end up going deeper into my corvette engine. So I need some advice on what I should &/or perhaps not do. My vette is an 89 w/around 72k miles on her. I finally decided to pull her from close to a decade of hibernation to...

garage.grumpysperformance.com

http://garage.grumpysperformance.com/index.php?threads/testing-1985-89-m-a-f-sensor.1475/#post-43635

http://garage.grumpysperformance.co...lay-switch-locations-and-info.728/#post-25471

http://www.compcams.com/Community/Artic ... 1737510521

do you need a dual 58mm throttle body on your TPI?

I get asked frequently if installing a larger than the stock 48mm TPI throttle body will significantly help on a corvette engine, Ill save you some reading right off if you want, yes a 58mm can potentially increase hp if your engines highly modified and your still useing a stock 48mm throttle...

garage.grumpysperformance.com

http://chevythunder.com/

http://www.superchevy.com/how-to/18459-chevrolet-corvette-c4-tpi-upgrades/

http://garage.grumpysperformance.com/index.php?threads/fuel-injector-resistance-reading.606/

http://garage.grumpysperformance.com/index.php?threads/fuel-line-sizing-return-vs-feed.3067/

http://garage.grumpysperformance.co...ed-a-dual-58mm-throttle-body-on-your-tpi.290/

http://garage.grumpysperformance.com/index.php?threads/throttle-body-size-52mm-vs-58mm.641/

http://garage.grumpysperformance.co...the-throttle-body-coolant-bypass-thing.10544/

http://www.hotrod.com/articles/hrdp-9812-10-common-efi-mistakes/

http://garage.grumpysperformance.co...ocity-vs-intake-runner-sizing.1099/#post-2152

http://mysite.verizon.net/vzezeqah/site ... ystems.pdf



http://www.eecis.udel.edu/~davis/z28/wi ... 21105.html

IF you check around on the site theres a good deal more cylinder head , port, and cam, flow data and info on how to match components, if youve got questions please post, as IVE got only about 10% of the info on my hard drives posted currently

the first thing you need to do is step back and decide ,anytime you plan engine upgrades you need to take the SYSTEM approach, as no one component alone will function to its full potential unless matched to other components that are designed to operate at the same rpm, flow and power rates, if your going to swap to far better heads, a larger duration cam, high efficiency & low restriction scavenging exhaust and higher numerically rear gearing , higher compression, possibly larger displacement and a low restriction exhaust so that a huge flow rate on the intake flow increase can be effectively used, or if your basically adding JUST an intake to add some upper rpm flow to a basically stock engine where you don,t intend to do other major mods, the difference in what your trying to do and the results your likely to see will dictate a totally different approach. a simple intake change alone won,t produce outstanding results, its the old (weakest link in the chain deal) even if the intake flow is potentially far better, if the heads and cam won,t allow the intake to flow up to its full potential you won,t see a big change, and too get a noticeable change, all three components need to be upgraded
the most common mistake made by many people is that they fail to look at an engine as an interconnected group of component sub systems and they don,t realize that changes to a single component, no mater how much potential that component has,is not going to allow that component or change in the potential to be realized until all the matched and supporting systems have similar potential.
EXAMPLE ,
the heads may be capable of flowing (x) on a stock engine but with careful selection of a cam with the correct duration and lift, and with a tuned header, and matching valve train mods along with some port and bowl clean-up the resulting improvements can be significantly more impressive.
http://www.jegs.com/webapp/wcs/stores/servlet/topcategory_10001_10002_-1

https://www.ebay.com/itm/Weiand-908...For-Use-With-144-174-Blower-Kits/400669303867


https://www.ebay.com/itm/Weiand-622...r-Small-Block-and-Big-Block-Chev/112273744933


IF YOU HAVE THERMOSTAT TO THROTTLE BODY CLEARANCE ISSUES

Have one to sell? Sell now
Weiand 6221 Offset Thermostat Housing Adapter For Small Block and Big Block Chev
your problem is VERY COMMON, if the throttle body and thermostat housing has a clearance issue on some modified EFI intakes, heres the usual cure
http://garage.grumpysperformance.com/index.php?threads/is-backpressure-hurting-your-combo.495/

http://garage.grumpysperformance.co...alves-and-polishing-combustion-chambers.2630/

http://garage.grumpysperformance.co...e-springs-and-setting-up-the-valve-train.181/

http://garage.grumpysperformance.co...lsa-effects-your-compression-torque-dcr.1070/

http://garage.grumpysperformance.com/index.php?threads/more-port-flow-related-info.322/

http://garage.grumpysperformance.co...2-bbc-rebuild-but-think-things-through.13604/

http://garage.grumpysperformance.co...t-intake-on-oval-port-heads.13146/#post-69975
use this calculator
http://www.rbracing-rsr.com/runnertorquecalc.html

it should open your eyes, the stock TPI runner is optomised for 3400rpm on a 350, with its 1.7 sq inch cross section,swap to, for example the larger FIRST TPI, it jumps to 4800rpm, with its un ported 2.4 sq inch cross section, that alone is worth almost 100 hp is both engines made the same peak 400 ft lbs of torque at there optimum rpm peaks, but your likely to find the larger ports more efficient.
that's one reason the MINI-ram advertises it can make 100 more hp than a TPI, its not that the mini-ram, FIRST,or STEALTHRAM intakes that great, its that THEY ALL allow the engine to breath far higher into the engines upper rpm range where the stock GM TPI has become exceptionally restrictive to flow compared too,the mini-ram, FIRST,or STEALTHRAM intake

when you combine head flow with intake flow in most cases those measurements were done on the individual components on a flow bench, if the heads flow 200cfm at .500 lift and the intake flows 190cfm that in no way indicates that you'll reach similar numbers with all the components bolted together.
remember your valve is only at full lift (AND THAT'S WELL UNDER .500 with a stock cam) for a very few degrees in the 720 degree repeat cycle, so your very unlikely to even approach those flow numbers, with the stock cam that has about a 195 intake duration, at .050 lift, that's about 27% of the total cycle even if the cam was INSTANTLY fully open and held open for the full 27% of the time, but the truth is its open for a great deal less time at peak flow.

the stock TPI head flow is in the 190cfm-200cfm range, that matches the stock head flow rates,and the stock cam lift.
read thru the posted links theres a good deal of useful info, but keep in mind its a balanced system your after designed to operate in a known rpm range and displacement, its almost always better to increase flow rates and engine displacement, but most components must match, a killer cam designed to operate at 6700rpm won,t work well with heads that effectively become a restriction at 5500rpm, an intake designed to maximize power at 5500rpm should be matched to a cam and heads designed for a similar rpm band and a drive train designed or allow the engine to opperate in that same rpm band 90% of the time.
larger displacements, higher compression ratios and carefully matched components can produce an engine that has impressive torque, excellent durrability and a car thats fun to drive at BOTH the track and on the street!
peak horsepowers nice for bragging but having instantly available massive torque in your cars intended rpm band, matching your trans and gear ratios, is far nicer on the street, and almost as fast or just as fast on the track. keep in mind your cars drive train ,trans stall speed and rear gearing must match the power curve.

Ive tested a bunch of IMPROVE TPI REPLACEMENT style intakes on my cars, one of the best is the ported HOLLEY STEALTH RAM, but theres CLEARANCE ISSUES on some cars as its 10" tall and a corvette for example has only 9" of hood clearance so a CUSTOM PLENUM or a HOOD SCOOP is MANDATORY TO RUN ONE on a corvette for example !


viewtopic.php?f=52&t=92



the stock TPI intake flow rarely reaches 196cfm

http://dtcc.cz28.com/flow/index.htm

IF your keeping the stock heads and cam , or even just the stock heads and a decent upgraded cam you'll want to keep the basic engine configuration similar to the TPI, in the rpm range and power curve configuration, but you want to add flow to boost the hp, the SUPER RAM, or the FIRST TPI, but keep in mind the results you see won,t reflect the intakes true potential without better heads and a cam with more duration that will allow the heads, intake and cam to flow the necessary air to produce significantly higher power levels.



both those intakes are designed to maximize torque in about the 1800rpm-5800rpm band(depends on porting, heads,displacement, compression, head flow, exhaust scavenging etc.

they will maintain the basic rpm band but at higher flow rates,thus youll have noticably more power without getting into the short block too much,

the mini-ram and stealth ram are both designed to operate a a noticably higher rpm band (about the 3500rpm-6700rpm band) so better heads and higher (3.54:1-3.73:1)rear gear ratios, larger durration cams (usually in the 220-min-to at least 239-245 dur max at .050 lift) range and higher compression ratios become almost mandatory if you want to maximize those intake manifolds potential.

http://stealthram.com/flowcomparison.html
(keep in mind in some cases the intakes are ported and in some cases they were right out of the box)

Here's some flow figures, right off the manufactures sites in many cases. Keep in mind the concept of the chains weakest link. It does ABSOLUTELY no good to match a base or runners on a TPI intake that flows 250cfm if the other part flows 200cfm. You'll still only flow 200cfm. The HOLLEY STEALTH RAM FLOWS at 275cfm out of the box,(minor port clean-up work) and can easily reach 300cfm with minor port work. The stock TPI has a hard time flowing 230cfm even with minor port work. Look here. Most of this info is right off the Accel, Holley, Edelbrock, and TPIS sites. Add a little math and the results become much clearer!!!

Intake......runner length .... port in...... out
Stock GM Base----- 6.375"------------- 1.47"------- 1.96x1.20
TPIS base------------6.125"------------- 1.75"------- 2.09x1.28
Accel base-----------6.125"------------- 1.75"---------2.09x1.28
Holley base--------- 6.000" ------------ 2.30â€-------- 1.90x1.23 (2.337 sq inches)

Runners
Stock TPI-------- 7.250"------1.470" round(1.70 sq inches)
SLP -------------- 6.625"------1.600" round (2.01 sq inches)
Accel LTR------- 6.625"------1.615" round (2.05 sq inches)
TPiS-------------- 7.625"------1.660" round (2.168 sq inches)
Mini ram --------3.500â€
stock MRII with 1204 (AFR 195) ports, 58MM - 265 cfm
stock MRII with 1206 (AFR 220) ports, 58MM - 281 cfm
MRII clean-up, 1206 ports, 58MM - 292 cfm
MRII cut, weld, port, etc, 58MM - 321 cfm
LT1 ----------3.000â€

Runners (measured individually)
Stock........................................................................................................................................203.17 cfm
ACCEL.....................................................................................................................................242.02 cfm
Extrude/ACCEL........................................................................................................................275.83 cfm
Super Ram................................................................................................................................289.18 cfm
Intake manifold with 3/8 inch radiused inlet .............................................................................222.45 cfm
Holley stealth ram ………..........................................................................................................275.00 cfm


Stock intake manifold with runner
Stock.........................................................................................................................................198.72 cfm
ACCEL......................................................................................................................................213.52 cfm
Extrude/ACCEL.........................................................................................................................217.11 cfm
Super Ram.................................................................................................................................220.67 cfm
Holley stealth ram ….................................................................................................................275.00 cfm
ACCEL Hi-Flow intake manifold with 3/8 inch radiused inlet.....................................................251.51 cfm
ACCEL Hi-Flow intake manifold with runner Stock...................................................................215.83 cfm
ACCEL......................................................................................................................................232.53 cfm
Extrude/ACCEL.........................................................................................................................243.21 cfm
Super Ram.................................................................................................................................240.24 cfm
Extrude-Honed ACCEL Hi-Flow intake manifold with 3/8 inch radiused inlet.............................275.83 cfm
Extrude-Honed ACCEL Hi-Flow intake manifold with ACCEL runner.......................................266.94 cfm
Edelbrock Performer RPM manifold (Stock)...............................................................................286.51 cfm
Edelbrock Victor Jr....................................................................................................................275.24 cfm


Runner Length


Stock TPI manifold ...................8†...............runners 11.25â€............... cylinder head 6â€.............total 25.25â€
Accel super ram manifold........ 8â€................runners 7.00â€............... cylinder head 6â€............ total 21.00â€
Holley stealth ram manifold .....6.26†................................................. cylinder head 6â€............ total 12.26â€
Edelbrock performer RPM ...........................runners 6.00â€................ cylinder head 6â€............ total 12.00â€
Edelbrock Victor Jr .......................................runners 5.50â€................ cylinder head 6â€............ total 11.50â€




Now playing with the figure in the calculators below, what you'll find is that if your using a 350 size engine as a guide, the tpi runner length is ideal for peak tq 3427rpm and 2700-4000rpm for peak hp.

The Accel Super Ram is ideal for peak tq at 4032rpm and 3300rpm-4800rpm for peak hp.

Holley's Stealth Ram runner length is ideal at 4700 for peak tq and 5618rpm to 6282rpm for peak hp.

The TPIS Mini Ram and LT1 intakes are ideal for peak tq at about 5200rpm and 7244rpm to 8101rpm for peak hp.

By hp peak, in the above lists, I'M REFERRING TO THE RPM RANGE WHERE combination of cross sectional area MATCHED TO THE plenum to INTAKE valve distance WHERE THE internal AIRFLOW HARMONICS TEND TO INCREASE THE CYLINDER FILLING EFFICIENCY (WHERE THE INTAKE WILL TEND TO PULL THE MOST HP). Now KEEP FIRMLY IN MIND the engines tend to enter valve float and get close to engine red line by 6300-6700rpm depending on your combo. After running all the available combos, I've found a HOLLEY STEALTH RAM has been EXTREMELY EFFECTIVE on several engines tested. CURRENTLY THE STEALTH RAM SEEMS TO
BE THE CHOICE, ESPECIALLY IF MATCHED TO GOOD CYLINDER HEADS AND THE CORRECT
CAM.

Came across this info while doing some research and thought I'd share.

http://www.hobracing.com/tech/tpi_flow.asp
TPI Intakes and runners

The following airflow tests were performed on the University of Northwestern Ohio's SuperFlow SF600 Flow Bench. All CFM values are corrected for airflow at 28 inches of water. Injector flow rates are flowed at 43.5 PSI on an injector flow bench using test fluid with same density as gasoline.

AirFlow

Stock TPI/LT1 48mm Throttle Body w/o airfoil -- 783.0 cfm

Stock TPI/LT1 48mm Throttle Body w/ airfoil -- 821.9 cfm

TPI/LT1 52mm Throttle Body w/o airfoil -- 848.9 cfm

TPI/LT1 52mm Throttle Body w/ airfoil -- 898.8 cfm

Stock 98 Camaro 3800 II Throttle Body -- 554.3 cfm

Stock TPI Bosch MAF sensor w/ screens -- 517.8 cfm

Stock TPI Bosch MAF sensor w/o screens -- 658.4 cfm

Stock 87 GN 3.8L Turbo AC MAF sensor w/ screen -- 584.2 cfm

Stock 86 2.8L AC 5-wire MAF sensor w/ screen -- 576.2 cfm

Stock 96-up AC 3100 V6 MAF sensor w/ screen -- 616.4 cfm

Stock 96-up AC 3100 V6 MAF sensor w/o screen -- 670.7 cfm

Stock 94-up LT1 MAF Sensor w/o screen -- 719.0 cfm

Stock 85-87 Firebird TPI airbox mid piece -- 499.3 cfm

Stock 4.3/5.0/5.7 2bbl TBI complete -- 574.1 cfm (dry)

Stock 4.3/5.0/5.7 2bbl TBI w/o injectors -- 584.7 cfm

Stock 3800 vin L throttle body w/ screen -- 419.1 cfm

Stock 3800 vin L throttle body w/o screen -- 444.8 cfm

4bbl MPFI Holley Throttle Body -- 1287.6 cfm

Another source sent in these flow numbers

Flow and HP ratings for Throttle-bodies:

Flow (cfm) Max. NA HP
Stock 668 300
Stock w/airfoil 710 350
52MM w/airfoil 835 400
54MM (AS&M) 900 450
58MM 1050 500


TPI Intakes and runners flow rates

Stock intake manifold with runner
Stock....................198.72 cfm
ACCEL................213.52 cfm
Extrude/ACCEL....217.11 cfm
Super Ram............220.67 cfm

the stock TPI has a hard time flowing 230cfm even with minor port work, look here
most of this info is right off the accel,holley,edelbrock, and TPIS sites, add a little math and the results become much clearer!!!

Intake....... length ....... port in -- out
Stock GM Base--- 6.375"------ 1.47"- 1.96x1.2
TPiS base------ -6.125"------ 1.75"- 2.09x1.28
Accel base----- -6.125"------ 1.75"- 2.09x1.28
Holley base------- 6” runner 2.3”- 1.9”x 1.23 (2.337 sq inches)
Runners
Stock TPI----- -- 7.250"------1.470" round(1.70 sq inchs)
SLP ----------- - 6.625"------1.600" round (2.01 sq inchs)
Accel LTR------- 6.625"------1.615" round (2.05 sq inchs)
TPiS----------- 7.625"------1.660" round (2.168 sq inchs)
Mini ram -----3.5”
LT1 ----------3”

Runners (measured individually)
Stock....................203.17 cfm
ACCEL................242.02 cfm
Extrude/ACCEL...275.83 cfm
Super Ram............289.18 cfm
Intake manifold with 3/8 inch radiused intlet.............................222.45 cfm
Holley stealth ram ………..275cfm

Stock intake manifold with runner
Stock....................198.72 cfm
ACCEL................213.52 cfm
Extrude/ACCEL....217.11 cfm
Super Ram............220.67 cfm
Holley stealth ram …..275cfm

ACCEL Hi-Flow intake manifold with 3/8 inch radiused inlet.........251.51 cfm

ACCEL Hi-Flow intake manifold with runner
Stock....................215.83 cfm
ACCEL................232.53 cfm
Extrude/ACCEL....243.21 cfm
Super Ram............240.24 cfm

Extrude-Honed ACCEL Hi-Flow intake manifold with 3/8 inch radiused inlet ...............275.83 cfm
Extrude-Honed ACCEL Hi-Flow intake manifold with ACCEL runner ..............266.94 cfm
Edelbrock Performer RPM manifold (Stock)..........286.51 cfm
Edelbrock Victor Jr. ............275.24 cfm

HOLLEY STEALTH RAM
the HOLLEY STEALTH RAM FLOWS at 275cfm out of the box, and has the potential when matched to the correct heads and cam to totally out flow most other intakes available,can easily reach 300cfm with minor port work and costs much less
Stock…………………………… 275cfm
Ported…………………………..300cfm

Runner lengths
Stock tpi manifold 8” runners 11.25”, cylinder head 6” total 25.25”
Accel super ram manifold 8” runners 7” cylinder head 6” total 21”
Holley stealth ram manifold 6.26” ” cylinder head 6” total 12.26”
Edelbrock performer RPM runners 6” ” cylinder head 6” total 12”
Edelbrock vic jr , runner length 5.5” ” ” cylinder head 6” total 11.5”



Also interesting TPI mods. Not so sure I agree with the one on bumping up the initial timing.
http://www.hobracing.com/tech/tpi_mods.asp


Basic TPI modifications
Friday, May 23, 2014





Basic TPI Mods: by DEBBIES87

There are a few basic mods that should be done to any TPI car, I call these "entry-level" modifications.

1) Cut the air box open without letting air in the engine without going through the air filter & remove the additional plastic piece below the air box to get more air into the engine.

2) Modify the mass air sensor; remove the screens, & and if your brave cut down the fins.

3) Port the plenum (upper intake). There are two small ridges sticking up in the entry-behind the throttle body, remove these. The throttle body openings are already 52mm, so don't go crazy when porting.

4) While the plenum is off for porting, it is now a good time to get a adjustable fuel pressure regulator & a MAT sensor relocater kit. The Adj. FPR will aid in tuning, and the new MAT sensor will improve throttle response as well. The new LT1 style MAT sensor is placed in the air box instead of the plenum, this allows it to read cooler air and advance the timing accordingly.

5) Advance the base timing to 12-13 degrees. Note: the harmonic balancers on these cars tend to drift with age, adjust timing to where the car still starts good and doesn't detonate.

6) If legal in your area, gut the catalytic converter and remove the smog pump belt (85-87), or run a shorter serpentine belt to bypass the pump (88-92); you will need to remove the smog pump on the 88-92's to reroute the belt properly. Check local smog laws first.

7) On automatic cars, adjust T.V. cable (throttle valve cable), so that the car shifts out between 4200-4500 RPM under wide open throttle. TPI motor power drops off drastically after 4500-4700 RPM, they peak at about 4200-4400 RPM. No need to over-rev these motors.

8) Bypass fan relay to make fans come on manually, or install aftermarket relay to turn on fans sooner.

All together these mods should make the car perform like it should have from the factory, gains should be between .6-.9 tenths of a second from these modifications.




T.V

The intake ports on the STEALTHRAM as it comes from HOLLEY. It fits the Felpro #1205 gasket port size.




the stock cam is designed for maximum cylinder fill efficiency at no more than 5500 rpm,
and that requires tuned headers and a low restriction exhaust(not the stock OEM set up)

 

[grumpyvette]

Re: just how restrictive are the stock TPI engine components
typical 1986 tuned port corvette engine

increasing power is in large part the result of increasing the amount of air/fuel mix you can efficiently pack into and burn in the cylinders and the number of power strokes per second that the engine can produce in its effective power range.

if your goal is too significantly boost the power of that c4 corvettes tuned port SBC engine, taking the time too carefully read these threads will be very helpful in reaching that goal.

http://garage.grumpysperformance.com/index.php?threads/ideal-tpi-build.12203/#post-59273

http://garage.grumpysperformance.com/index.php?threads/a-well-designed-c4-exhaust.786/#post-46459

http://garage.grumpysperformance.co...ps-on-building-a-tpi-383-c4.10434/#post-43430

http://garage.grumpysperformance.co...hing-the-drive-train-to-the-engine-combo.741/

http://garage.grumpysperformance.co...-stock-tpi-engine-components.1509/#post-74581

http://garage.grumpysperformance.co...pans-that-fit-the-c4-corvette.3071/#post-8156

http://garage.grumpysperformance.co...gine-to-match-the-cam-specs.11764/#post-55651

http://garage.grumpysperformance.co...rger-intake-runners-l98-tpi.13785/#post-72541

http://garage.grumpysperformance.co...ttle-body-size-48mm-52mm-58mm.546/#post-32516

http://garage.grumpysperformance.co...ther-efi-intake-manifold-info.431/#post-32491

http://garage.grumpysperformance.com/index.php?threads/tbucket-engine-project-dart-shp.3814/


read the links
http://garage.grumpysperformance.co...at-manifold-air-temp-sensor.10349/#post-42530

http://garage.grumpysperformance.co...elay-switch-locations-and-info.728/#post-9217

http://garage.grumpysperformance.com/index.php?threads/cooler-denser-air.8961/#post-54496
stealthram base

stealthram base

you may be amazed to find a great deal of research and testing has been done and theres actually proven facts rather than random guess work to use in planing a well built engine combo

stock un-ported runner entrances

porting helps flow significantly
JUST A NOTE, in my experience,if your into building a TPI the secret is in matched components and use of great heads, find heads that flow a MINIMUM of 250cfm at .500 lift, use a 10:1-10.5:1 cpr 36-42 lb injectors
A PROPERLY PORTED AND MODIFIED STEALTH RAM INTAKE,

youll want to read these threads

http://www.grumpysperformance.com/2376432_100_full.jpg
http://www.grumpysperformance.com/2376432_101_full.jpg
http://www.grumpysperformance.com/2376432_102_full.jpg
http://www.grumpysperformance.com/2376432_103_full.jpg
http://www.grumpysperformance.com/2376432_104_full.jpg
http://www.grumpysperformance.com/2376432_105_full.jpg
http://www.grumpysperformance.com/2376432_106_full.jpg
http://www.grumpysperformance.com/2376432_107_full.jpg
http://www.grumpysperformance.com/2376432_108_full.jpg
http://www.grumpysperformance.com/2376432_39_full.jpg
http://www.grumpysperformance.com/2376432_41_full.jpg



http://www.cis.udel.edu/~davis/z28/buil ... e/porting/

http://www.gmtips.com/3rd-degree/dox/ti ... t/port.htm

http://www.cis.udel.edu/~davis/z28/buildup/plenum/

viewtopic.php?f=52&t=1070

http://noel.prodigitalsoftware.com/NCtpi.html

http://garage.grumpysperformance.com/index.php?threads/c4-corvettes-fuel-system-info.67/#post-37351

http://forum.grumpysperformance.com/viewtopic.php?f=32&t=1401&p=8895&hilit=start+sequence#p8895

http://garage.grumpysperformance.co...ey-grumpy-do-i-need-bigger-injectors.5583/#po

http://garage.grumpysperformance.com/index.php?threads/calculate-fuel-injector-size.1200/#post-4041

http://garage.grumpysperformance.co...easonably-effective-tpi-combo.1060/#post-2031

http://garage.grumpysperformance.co...-other-efi-intake-manifold-info.431/#post-530

http://garage.grumpysperformance.com/index.php?threads/can-you-get-there-with-tpi.10494/#post-44299

http://garage.grumpysperformance.co...g-tpi-crossfire-or-lt1-vette.1401/#post-39419

http://garage.grumpysperformance.co...-1985-corvettes-cold-start-9th-injector.2861/

heres a few pictures that were posted on line of the EDELBROCK TPI BASE that has larger runners than the stock TPI base, keep in mind that having a killer set of high flow runners or a ported plenum won,t result in much of a air flow gain with a restrictive stock base and even with a high flow runners, and base and plenum the stock heads won,t show much flow improvement, ...you'll require both better flowing intake components and a set of much better cylinder heads to increase the flow rates, but even then, if you don,t use a cam with enough duration and lift high flow components can,t fill the cylinders and build more power unless the valves are held open far enough and long enough to allow a significant improvement in the combos air flow potential

KEEP IN MIND THERE ARE OTHER SOURCES FOR HIGH FLOW TPI STYLE BASES, LIKE THE FIRST TPI CLONE
RUNNERS AND BASE SHOWN BELOW
http://www.firstfuelinjection.com

http://firstfuelinjection.com/PDRM1966.JPG

Post in thread 'Hello, 91 corvette building a 383'

Jun 30, 2022

that's certainly easy to do if you have a reasonable budget and some mechanical skills and knowledge
the key in my experience is correctly matching the selected components.
the main issue is that the c4 corvette has HUGE performance potential but many of the OEM parts like the cylinder heads intake manifold and cam are very restrictive.
Id strongly suggest you look over and read a few threads links I'LL provide before you decide on the components you select,

personally I'd strongly suggest you start with the info in the links below, yeah,
it will take...

• Grumpy

intake comes with a new throttle body

https://www.firstfuelinjection.com/services.html

https://nebula.wsimg.com/2be547087c...4B6CCFD3E432CCDD0&disposition=0&alloworigin=1

matching that first intake to good heads like the 200cc brodix IK or 210 cc AFR , etc, and select a decent quality hydraulic roller cam that will alow the ports to flow, The crower 00471 or the more agreasive CRANE 119651 come to mind!
youll need a 3000 rpm stall concerter and a 3.54:1-3.73:1 rear gear and a trans cooler and shift kit
BUY the FIRST intake and port it , correctly done it has the potential to feed 600 hp
while most of the other options struggle at 450-500-hp

 

[grumpyvette]

Re: just how restrictive are the stock TPI engine components

the one major factor most of you are ignoring is that all the intake manifolds are designed to operate at different rpm ranges , and REQUIRE a cam and cylinder heads that will flow the MATCHING CFM FLOW RATES and in the intended RPM BAND , and obviously the engines displacement, and compression ratio must be compatible with the cam timing and lift and if the compression and cam used does not exactly match the intakes rpm range the intake will produce far lower numbers!


EXAMPLE
my PORTED STEALTH RAM produced far better peak power with both a CRANE 119661 and CROWER 00471 than with cams that worked correctly with the PORTED TPI with high flow runners, because the HSR is designed to operate at a HIGHER AVERAGE RPM BAND than the stock type TPI design intake. you could get impressive gains from that FIRST intake with a bit more mid rpm torque due to the longer runners, the HOLLEY Stealth ram also must be ported to work to near it full potential.
READ THRU THIS
viewtopic.php?f=55&t=1745&p=4378&hilit=+stealth#p4378
changing from the 52mm to a 58 mm throttle body might seem like its going to give some significant improvement,
but its usually not nearly as effective as simply doing some manifold port clean-up.
and remember youll want too keep the fuel/air ratio consistent with making maximum torque , this very often requires an upgrade in fuel injector size,
and occasionally a bigger more effective fuel pump, Ive seen lots of guys slap on killer heads and a decent intake then have that deer in the head lights look when the engine with a larger cam thats designed for max peak power, basically sucks due to the cams loss of low rpm effective compression and the lack of fuel to supply the new higher rpm air flow rates, thus both ends of the power curve suffered
the added duration on a cam that allows the engine to breath at higher rpms reduces the lower rpm torque as the valves close later so theres less trapped fuel/air being burnt per power stroke, but in theory the inertial ram effect and the higher number of power strokes per minute , and increased exhaust scavenging increasing the cylinder fill efficiency, that easily off sets that, lower rpm loss, for impressive gains in the upper rpm range, but if you can supply the fuel required the result is both ends of the power curve suffer.
a 52 mm throttle body can easily supply a 383 at 6400 rpm , its other factors that generally restrict power

Flow (cfm) Max. NA HP
Stock 668 300
Stock w/airfoil 710 350
52MM w/airfoil 835 400
54MM (AS&M) 900 450
58MM 1050 500

stock un-ported runner entrances

porting helps flow significantly
READ THE LINKS
http://garage.grumpysperformance.co...-heads-for-small-block-chevys.3293/#post-8709

http://garage.grumpysperformance.co...8mm-throttle-body-on-your-tpi.290/#post-22467

http://garage.grumpysperformance.com/index.php?threads/selecting-an-efi-intake.1231/#post-20032

http://garage.grumpysperformance.com/index.php?threads/how-big-a-fuel-pump-do-you-need.1939/

http://garage.grumpysperformance.com/index.php?threads/calculate-fuel-injector-size.1200/
the one major factor most of you are ignoring is that all the intake manifolds are designed to operate at different rpm ranges and if the compression ratio fails to be correctly matched to the cam and if the cam used does not exactly match the intakes rpm range the intake will produce far lower numbers!
then your also ignoring the fact that once the intake flow exceeds the heads flow potential , the intake can show no significant gains past that heads flow level, significantly reducing the hp/tq numbers the intake test will show yet the intake still may have far greater potential and the fact that the larger the displacement and higher the compression the more effective the high flow intakes become!

my PORTED STEALTH RAM produced far better power with both a
CRANE 119661
http://www.cranecams.com/product/cart.p ... il&p=24188


and CROWER 00471s

than with cams that worked correctly with the PORTED TPI with high flow runners, this cam below,worked great at the track, on a 406 sbc I helped build for a friend,with AFR 210cc heads,hooker headers and a 10.5:1 cpr with a manual transmission and 3.73 rear gears
crane 119681
http://www.cranecams.com/product/cart.p ... il&p=24190

but had less than ideal street manors,

you might find these threads below useful
most of the current low rise 4 barrel intakes designed for street use fall in the 240cfm-260cfm range in stock out of the box form, the better single plane, intakes tend to run 20cfm or so higher, either style can be ported to increase the flow rates.
CALCULATORS
http://www.wallaceracing.com/calcafhp.php

http://www.wallaceracing.com/calchpaf.php

http://www.rbracing-rsr.com/runnertorquecalc.html

http://horsepowercalculators.net/intake ... old-design

https://fuelinjectorclinic.com/flow-calculator

https://www.injectorrx.com/injector-size-calculator/

https://www.witchhunter.com/injectorcalc1.php

http://www.raceworks.com.au/calculators/injector-hp-calculator/

http://www.rcfuelinjection.com/Technical

http://www.enginelabs.com/news/calculating-fuel-demands-and-injector-sizing-with-efi-university/

AUTOWIZ POSTED THIS INFO

I love building fuel injection systems and tuning them. I have put together a few packages to correct C4 EFI systems and I have another great idea for an aftermarket EFI conversion for the LT1/LT4 motors. To help get away from that optispark. Without tearing down the front of the LT engine.

When LS1 first came out it had a bigger throttle body than LT1 but notably it just had 1 throttle blade instead of the 2 small things inside of the LT TB. This early LS throttle body had a 3-bolt flange. Later on in 2005 when LS2 came out GM moved to a larger 92mm throttle body with a 4-bolt flange. This 92mm throttle body size is the standard of the day and for all the american V8's we love to play with we really don't see sizes smaller than this.

The stated goal of this EFI conversion is higher HP support through greater airflow. That is this would be a good swap if you have also swapped the 5.7 out of your C4 for something with greater than 400ci displacement. Or are running a hot cam with numerically lower LSA. This will let you keep the MAP sensor reading 105kpa at WOT.

The 92mm cable operated throttle body complete with GM IAC and TPS can be had right here: Throttle Body 92mm with TPS IAC Throttle Position Sensor For LSX LS LS1 LS2 LS7 | eBay

That flange is big and square and will not bolt to any LT1/LT4 intake manifold. However, with this elbow that 92mm t.b. will bolt right up to a 4150 carb flange: HOLLEY 4150 FLANGE EFI INTAKE ELBOW - BLACK - 300-240BK

And this intake manifold here will bolt right up to the vortec style heads and provide a distributor hole, a 4150 carb flange, and fuel injector ports, and even comes with little fuel rails: https://www.jegs.com/i/Holley/510/3...Ar9w2JWVoUfvZUqVxl7QHSJMq4YoQQLgaAmRIEALw_wcB

The fuel injectors need to be sized for the engine's output, fuel type, and ultimately demand.

This should be setup for sequential fueling and so a Dual Sync distributor should be used for this setup. Like this: Holley EFI 565-200 Holley EFI Dual Sync SBC/BBC Distributor

And then we can apply this EFI kit from Holley: Holley EFI 550-936 Holley EFI Terminator X Universal MPFI Kit


This kit is for higher engine output at higher RPM and is designed around a single plane intake and large throttle blade. This kit will do best with a manual transmission as it will let you wind out the engine as far as your valvetrain will allow. If we wanted to apply this to an automatic C4 with 4L60E and a loose converter then instead of the above Terminator X kit we would need a Terminator X Max kit like this one here: Holley EFI 550-942 Holley EFI Terminator X Max - Universal MPFI Kit

 

[Doodad]

Great info Grump I just wanted to chirp in here, To get those pesky Stealth to fit under a low slung hood just cut em like this:http://www.digitalcorvettes.com/forums/showthread.php?t=59726 or this:http://forums.corvetteforum.com/c4-general-discussion/2073962-holley-stealth-ram-for-your-c4-l98-2.html ,cool article you have to be confident to cut in to your brand new $500 intake :lol: Or this guy here..http://forums.corvetteforum.com/c4-gene ... l...here's some flow #'s for the TPI and Aftermarket Intakes(i dont know if they are accurate)...http://forums.corvetteforum.com/c4-tech ... ow-s.html..

 

[grumpyvette]

Re: just how restrictive are the stock TPI engine components

none of the you links posted work for me,
and no, I designed and tested a completely new plenum rather than cut up the old O.E.M. plenum as there were several very obvious areas that could be improved, research showed it was a good basic design but it could be improved a great deal, provided you have a mill and a tig welder and a good basic understanding of air flow and where the O.E.M. intake was restricting flow,as you saw I've got all the tools required and have tested easily a dozen or more plenum designs, theres no way to get the max potential flow characteristics from a cut and patch based on the original plenum.
keep in mind HOLLEY can't take the time and effort required to maximize the intakes potential and still maintain an economically viable to market intake platform, that's one reason why they based the stealth ram on a previously designed carburetor equipped tunnel-ram, and made the required mods to get it to function as an EFI platform
I've found BRODIX I.K. heads are very good quality, and decent value per dollar,
for a high performance street/strip style engine
https://craftperformanceengines.com...nder-Heads--brodix_cylinder_heads_sbc_ik.html

trickflow 230cc makes a good racing sbc head choice

https://www.trickflow.com/parts/tfs-3241t001-c03

profiler 210cc is a good compromise race and street strip head
https://www.profilerperformance.com/176-sbc-23-degree-heads.html

https://www.summitracing.com/parts/afr-1055/overview/make/chevrolet
http://www.airflowresearch.com/210cc-sbc-race-cylinder-head/

- FIRST TPI Intake.(good choice)

intake comes with a new throttle body
properly matched to the correct parts that FIRST TPI intake produces a very noticeable boost in power,
over almost any other intake designed for brisk SBC street/strip type, performance.
install it on a 383-406 sbc with about 10.5:1-11:1 compression, carefully matched,decent 195-210cc heads,
a free flow exhaust, with long tube headers and low restriction exhaust systems,and and a 3000 rpm stall converter or manual transmission, and a 3.55:1-3.73:1 rear gears
and a cam like a crane 119661-or crower 00471 and of course 36 lb-38 lb injectors and you transform a TPI corvette.

related info
USE THE CALCULATORS to match port size to intended rpm levels... but keep in mind valve lift and port flow limitations
http://www.wallaceracing.com/runnertorquecalc.php
http://www.wallaceracing.com/ca-calc.php
http://www.wallaceracing.com/area-under-curve.php
http://www.wallaceracing.com/chokepoint.php
http://www.wallaceracing.com/header_length.php

https://www.profilerperformance.com/176-sbc-23-degree-heads.html

http://garage.grumpysperformance.co...olishing-combustion-chambers.2630/#post-48319

http://garage.grumpysperformance.co...r-flow-heads-the-best-choice.9415/#post-34274

http://garage.grumpysperformance.co...good-street-combo-your-after.5078/#post-14433

http://garage.grumpysperformance.com/index.php?threads/more-port-flow-related-info.322/#post-722

[/COLOR]
read thru this thread also
viewtopic.php?f=55&t=1745&p=4378&hilit=+stealth#p4378

OK IVE JUST GOT TO ASK?
why would you buy a 52mm vs a 58MM throttle body????
now PLEASE don,t get me wrong,
the 52MM has a nice improvement in air flow over the stock throttle body, but in most cases that extra air flow is not used, especially on a mild engine or one with stock gearing and displacement, and the 58mm won,t in most cases increase the performance, and yes IM well aware from testing that the MAF sensors and the intake manifolds , and heads are the big restrictions, and that with out inproving those areas the stock throttle body works just fine.
BUT NEITHER WILL THE 58MM HURT a damn thing EITHER??
I tried BOTH on my 383 with BOTH the TPI and STEALTH RAM intakes, (I borrowed a friends 52mm to test) and there was no real differance untill I was up in the 6000rpm range, and even then the differance was minor, but again WHY buy the smaller unit, that could potentially be a restriction with future mods done??
its NOT like a carb, you won,t get a big loss of throttle response, in fact I could detect ZERO difference once it was correctly tuned) or for that matter experience any down side to the larger unit provided of course your tuning skills are decent.
and before you guys get crazy, do some research!
I don,t remember ever seeing a dyno on anyone else s engine EITHER that showed a LOSS to the larger unit, just a few that showed no IMPROVEMENT in a particular application, and if your thinking of pointing out a lack of throttle response thats been repeatedly shown to be due to tuning issues like low fuel pressure, too small of injectors,or the TPS voltage was off the mark, the IAC was not set correctly or the ignition timing curve was not ideal, or in a few cases the compression ratio was to low for the cam selected, get the LCA or duration wrong for the application and AIR FLOW REVERSION in the runners CAN cause problems, like a bog when you transition from idle to W.O.T. almost instantly, but in no case IVE seen was the extra potential air flow a problem, especially once you realize that the plenum/ports carry only AIR, and the fuels injected in the last 4 inches of the runners.

for some reason many guys seem to think the throttle body size is far more restrictive than it is while IGNORING the fact that as your engines horse power expectations increase the need to supply fuel to the engine also will increase and they find the engines tendency to loose power at 4500 rpm-5000 rpm , and blame it on a lack of air flow exclusively, when in fact its generally BOTH a lack of fuel and air flow rates that cause the power curve to nose over as rpms increase.
yes youll need a larger flow rated set of fuel injectors AND A BETTER FUEL PUMP, if you plan to exceed 400 plus hp
Inj Flow Rate (@ 40psid) Naturally Aspirated hp (@ 0.50)
19 lb/hr 258 hp @ 85% Duty Cycle
24 lb/hr 326 hp @ 85% Duty Cycle
30 lb/hr 408 hp @ 85% Duty Cycle
32 lb/hr 435 hp @ 85% Duty Cycle
39 lb/hr 530 hp @ 85% Duty Cycle
42 lb/hr 571 hp @ 85% Duty Cycle
47 lb/hr 639 hp @ 85% Duty Cycle
60 lb/hr 816 hp @ 85% Duty Cycle
BTW To TEST an INJECTOR with a multi meter for OHMS resistance, remove the connector from the injector, push carefully in the middle of the locking clip, with your thumb, This will make the sides, and tips move OUT WARD in their connector slots allowing the tips that hold the injector into the connector to slide out of the way from the injector body, and you can then pull the sides away. WATCH the locking clip - IT can and WILL come off and get lost, if your not careful put your V.O.M. meter on OHMS and put the leads across the two connectors ON THE INJECTOR ,it should read about 11-16 OHMS in most cases, a few are designed to read up to 19 ohms, or as low as 9 ohms , BUT GENERALLY READINGS LOWER THAN 11 OHMS tends to point to a problem with the injector , The Ford motorsport injectors in the 24lb-hr flavor test a little lower (14.1-14.3 ohms) than the bosch's @ 22lbs/hr. (15.9-16.3) BUT ALL INJECTORS IN A SET SHOULD READ WITHIN ONE OHM OF EACH OTHER if its out of that range by a wide margin ITS MORE THAN LIKELY DEFECTIVE, checking the OHMS reading as a first step will frequently detect a defective injector, naturally using your trouble codes , a shop manual and a fuel pressure gauge won,t hurt and a shop scope , or engine analyzing software with a read out to your laptop computer helps and can further isolate the problem, at IDLE speeds placing a finger tip on the side of the injector will usually allow you to feel it (CLICKING) adding a couple cans of injector cleaner and about a pint of MARVEL MYSTERY OIL to a full tank of fuel can sometimes free a sticky injector that partly clogged, but don,t do it frequently as its very hard on the CATS and O2 SENSORS if done constantly

partly clogged injectors tend to reduce power and increase emissions

notice, the injector resistance is usually stated in the description

Brand: ACCEL
Product Line: ACCEL Fuel Injectors
Part Type: Fuel Injectors
Part Number: ACC-150826
Injector Advertised Flow Rate (lbs/hr): 26 lbs./hr.
Injector Advertised Flow Rate (cc/min): 269.0cc/min
Injector Impedance: 14.4 ohms
Driver Type: 12 V saturated circuit
Overall Height (in): 2.880 in.
Seat to Seat Height (in): 2.270 in.
Manifold O-Ring Outside Diameter (in): 0.573 in.
Fuel Rail O-Ring Outside Diameter (in): 0.574 in.
Outside Diameter (in): 0.943 in.
Injector Plug Style: Bosch/Amp-style
Wiring Harness Included: No
O-Rings Included: Yes
Quantity:

http://www.megamanual.com/v22manual/minj.htm

IF your thinking of installing a LT4 intake on the first generation small block chevy engine theres a few required mods that will be necessary.
I really hope you took the effort to read thru the links and sub links so you understand the changes required to get that lt4 style intake to fit and function,if your installing that intake on the first gen engine rather than the LT4 engine
obviously youll need the matched throttle body, injectors,gaskets, sensors and fuel rails and connections
obviously you'll need a crank triggered distributor-less ignition or modifications to use a distributor,THAT FITS AND CLEARS THE INTAKE and mods to route coolant flow to the water pump and block that the current LT4 intake was not designed for but can be modified for.

http://sethirdgen.org/LT1.htm



http://www.popularhotrodding.com/tech/0 ... rsion_ls1/

http://www.eecis.udel.edu/~davis/z28/lt ... onversion/

Id suggest the 24lb for a basically stock 350 TPI application

THESE LOOK STOCK (I'm using a similar 36 lb rated set in my 383 currently)
https://www.ebay.com/i/391440066276?chn=ps&dispItem=1

, if it takes you more than an hour or so to swap injectors out you need a great deal more practice
http://garage.grumpysperformance.com/index.php?threads/my-current-corvettes-383-combo.430/

THESE DON,T (I ordered these for my BBC swap)
https://fuelinjectorconnection.com/products/24lb-bosch-3-for-tpi
https://www.highflowfuel.com/i-2390...MIoLrr3KCN2gIVTbjACh2JdgspEAAYASAAEgKqbPD_BwE
https://www.texas-speed.com/p-3973-fic-80lb-bosch-injectors-for-ls-ev14-set-of-8.aspx

either choice , of these would work
keep in mind the cpu will read the sensor data and modify the injector pulse duration,
to provide the engine with the intended fuel/air ratio, and the difference in the rated size is of zero concern as long as its properly tuned.
the rated size limits the upper flow rate but has almost no effect on mid and lower rpm flow.

https://www.corvetteactioncenter.co...il-removal-fuel-injector-replacement-827.html

http://garage.grumpysperformance.com/index.php?threads/diagnoseing-tpi-lt1-problems.1241/

http://garage.grumpysperformance.com/index.php?threads/350-sbc-383-sbc-1980-malibu.14493/

http://garage.grumpysperformance.co...ive-are-the-stock-tpi-engine-components.1509/

http://garage.grumpysperformance.com/index.php?threads/c4-corvettes-fuel-system-info.67/#post-37351

http://forum.grumpysperformance.com/viewtopic.php?f=32&t=1401&p=8895&hilit=start+sequence#p8895

http://garage.grumpysperformance.co...ey-grumpy-do-i-need-bigger-injectors.5583/#po

http://garage.grumpysperformance.com/index.php?threads/calculate-fuel-injector-size.1200/#post-4041

http://garage.grumpysperformance.co...easonably-effective-tpi-combo.1060/#post-2031

http://garage.grumpysperformance.co...-other-efi-intake-manifold-info.431/#post-530

http://garage.grumpysperformance.com/index.php?threads/can-you-get-there-with-tpi.10494/#post-44299

http://garage.grumpysperformance.co...g-tpi-crossfire-or-lt1-vette.1401/#post-39419

http://www.dartheads.com/products/aitdo ... le_id/103/

http://www.superchevy.com/how-to/engine ... 6sc-major/


IVE POSTED THIS LINKED INFO BEFORE BUT IT MAY BE USEFUL HERE
as the sub links contain a great deal of related info

theres a good many more dyno tested combos in this thread
viewtopic.php?f=69&t=519

http://www.superchevy.com/how-to/vemp-0607-l98-engine-induction-system/

http://xtremecarzone.com.au/STORAGE/ART ... ptions.pdf
Id also point out that cam timing matched to the exhaust scavenging has a huge effect on potential intake flow rates

I think this may help

http://www.wallaceracing.com/Calculators.htm

http://www.wallaceracing.com/runnertorquecalc.php

http://racingfeed.com/downloads/chevy_flow_data.pdf

http://www.velocity-of-sound.com/veloci ... lator3.htm

http://2.3liter.com/Calc2.htm#MinCross



http://www.highperformancepontiac.com/t ... index.html

http://www.highperformancepontiac.com/t ... index.html



DON,T FORGET TO MATCH THE HEADER SCAVENGING RPM BAND TO MATCH THE INTAKE AND CAM TIMING AND ENGINE DISPLACEMENT
in a properly designed combo cam timing,and duration, intake port cross sectional area and header length and diameter will be matched to displacement, compression ratio and drive train gearing so every factor is designed to peak efficiency at near the upper 2/3rds of the intended operational rpm band, and keep the critical piston speed below the peak operational rpm range
WHAT GOES IN NEEDS TO GET DRAWN OUT
viewtopic.php?f=56&t=185

http://www.grumpysperformance.com/portflow1.jpg

http://www.grumpysperformance.com/portflow2.jpg

http://www.grumpysperformance.com/portflow3.jpg

http://www.grumpysperformance.com/portflow4.jpg

while reading thru the info below , keep in mind the combo of cylinder heads,you select,your exhaust headers,and the restriction the exhaust system behind those headers cause,your effective compression ratio, your cam timing and the design and flow limitations of the intake manifold you used all effect the results, a stock throttle body is a minimal restrictive factor compared to what the other components listed contribute in most cases

http://www.grumpysperformance.com/ttt1.jpg

http://www.grumpysperformance.com/ttt2.jpg

http://www.grumpysperformance.com/ttt3.jpg

http://www.grumpysperformance.com/ttt4.jpg

http://www.grumpysperformance.com/ttt5.jpg

http://www.grumpysperformance.com/ttt6.jpg

http://www.grumpysperformance.com/ttt7.jpg

http://www.grumpysperformance.com/ttt8.jpg

http://www.grumpysperformance.com/ttt9.jpg

http://www.grumpysperformance.com/ttt10.jpg

http://www.grumpysperformance.com/ttt11.jpg

http://www.grumpysperformance.com/ttt12.jpg

http://www.grumpysperformance.com/ttt13.jpg

http://www.grumpysperformance.com/ttt14.jpg

http://www.grumpysperformance.com/ttt15.jpg

 

[Doodad]

Ill try to fix the links, I meant cutting the stealth or mini ram, another good tip is to grind the front EGR port in the front of the plenum (But not to far you'll go clean through ruining the plenum) also knock the castings from the inside of runner tubes on the top of runner (The bottom lip was designed to rotate the air charge before entering the intake) Siamese and gasket match runners to plenum and intake then you can work on the heads to handle your new airflow.I prefer the stock lookin runners or stock but thats just me.

 

[grumpyvette]

Re: just how restrictive are the stock TPI engine components

if your considering use of the SBC HOLLEY single plane intake be aware it will require some careful hand porting to flow well, its a good design but the ports and runner entrances and plenum as it comes out of the box can use a good deal of custom porting to allow it to flow at near its potential, you can very easily boost flow 30 cfm per runner with a few hours with a die grinder, heres a few pictures of a HOLLEY EFI intake after the port and runner clean up work, the BBC versions still require some work to flow to their potential but are not as restrictive out of the box,
while several guys brought up valid points to check, Ive found that the one most commonly over looked in my experience is that the stock exhaust system, is highly restrictive, and the stock fuel delivery system is not adequate,for the potential power, the heads and intake, allowable air flow potential, are all restrictive, and the stock cam timing and lift is already near max as it was designed to produce about 260 hp,and operate at under 5700 rpm, if you try too add an additional 100-200 hp, and 1000rpm-2000rpm to the engines power band, and too the engines output youll quickly find this to be a factor.
http://www.secondchancegarage.com/public/186.cfm

http://noel.prodigitalsoftware.com/NCtpi.html

http://garage.grumpysperformance.co...oblem-sources-1987-corvette.15596/#post-93275

SBC (4160 carb size TB base)
http://www.summitracing.com/parts/hly-9 ... /overview/

BBC (RECTANGLE)(4160 carb size TB base)
http://www.summitracing.com/parts/hly-9 ... /overview/

BBC (OVAL)(4160 carb size TB base)
http://www.summitracing.com/parts/hly-9 ... /overview/

BBC (RECTANGLE) DOMINATOR SIZE TB
http://www.summitracing.com/parts/hly-9 ... /overview/

viewtopic.php?f=52&t=462&hilit=porting+help

 

[Grumpy]

A 305ci Engine Makes Big Horsepower Using a TorqStorm Supercharger
Any Port In The Storm: TPI gets boost
Richard Holdener Jan 5, 2018

http://www.superchevy.com/how-to/en...-big-horsepower-using-torqstorm-supercharger/
View Full Gallery
Old-timers who were around back during the original muscle car era will look back longingly on the engines that ruled the streets then: the 290hp 302, the 350hp 350, and the 375hp 327. Those of us cutting our performance teeth at the start of the second muscle car era will look back at a decidedly different set of muscle motors. To combat the Ford H.O. 302 in the Mustang, GM introduced a powerful 5.0L of its own. First available in L69 carbureted form, GM soon introduced the LB9 TPI 305 with Tuned Port Injection. Sure, they offered the L98 350 in the Corvette (and Camaro with an automatic), but the stick shift LB9 was the hot setup in an F-body back in the day. Despite an epic battle with the Blue Oval boys, the 305 never gained the respect it deserved. Lest we forget, the LB9 305 (or any 305 for that matter) is still a small-block Chevy, and that is one heck of a starting point.

OK sure, most 305 owners would gladly trade up to the larger 350, but rather than go the swap route, let’s take a look at some performance possibilities with the standard displacement. For those new to the small-block world, the difference between the 305 and the 350 is bore size. Both small-blocks share the same 3.480-inch stroke, but where the larger 350 runs a 4.000-inch bore, the 305 was saddled with a smaller 3.736-inch bore. The argument against the 305 is that the smaller bore size limits the breathing potential of the cylinder heads by shrouding the valves or outright limiting valve size. Both of these are true, but the real question for 305 owners is at what power level does this truly become limiting? If you are building a simple 375-400hp street/strip small-block, the 305 can get you there even with the limitations imposed by the bore size. If you want to take things beyond that level things get more difficult. That is, unless you add the great equalizer: boost!





To illustrate the potential of a boosted 305, we took an original LB9 TPI 305 small-block and added positive pressure from a TorqStorm supercharger. Prior to the pressurization, the small-block was treated to some performance mods: a performance cam, aluminum heads, and a much-improved induction system. The cam offered a 0.570/0.565-inch lift split, a 218/224-degree duration split, and 113-degree LSA. The cam was teamed with a set of Trick Flow Specialties (TFS) Super 23 175 aluminum cylinder heads. Designed specifically for the small-bore size, the Super 23 heads featured 175cc intake ports, a 1.94/1.50 valve package, and 56cc combustion chambers. Compared to their stock iron counterparts, the Super 23 heads from TFS offered sizable flow gains and were capable of supporting nearly 500 hp on the right combination. The final mod was to replace the long-runner, factory TPI intake with a Holley Stealth Ram intake and 58mm throttle body. Run with a Holley HP ECU, the modified LB9 305 produced 372 hp at 5,900 rpm and 353 lb-ft of torque at 5,000 rpm. The 305 was already off to a good start.



Boost for the modified TPI 305 engine came courtesy of the gang at TorqStorm. The centrifugal supercharger offered a number of desirable features, including billet aluminum construction, a proprietary ceramic bearing system, and coating of the internal components for temperature and wear control. While other blower manufacturers offer superchargers capable of exceeding 1,000, 2,000, or even 3,000 hp, TorqStorm designed their blower for real-world, daily driven applications. Capable of supporting over 700 hp on the right application, the TorqStorm supercharger was perfectly sized for our modified 305. The kit supplied by TorqStorm included the supercharger (with pulley), mounting bracket, and crank pulley assembly (including the hub-centric spacer). The kit also featured the belt and tensioner, which allowed us to successfully run over 10 psi of boost with no belt slippage. Also included were couplers, tubing, and a blow-off valve (BOV) to eliminate the pressure spike that occurs when lifting off the throttle at high rpm/boost. The BOV also eliminates boost buildup under cruise conditions. Installation was beyond simple, with no need to supply oil to the self-contained blower or drill and tap the oil pan to serve as an oil return.

Because the kit was originally designed for use with a carburetor (we ran it carbureted for John McGann and the boys over at our sister publication Car Craft), we had to improvise the discharge tube connecting the supercharger to the throttle body. Since we were going the DIY route, we decided to include intercooling into the mix. We happened to have an air-to-water intercooler from a test we did on a big-block. Since the core was capable of supporting the needs of 1,200+ hp, it had no trouble cooling roughly half that amount. After installation of the revised 3.5-inch discharge tube to match the inlet and outlet of the intercooler, we were nearly ready. We connected a vacuum/boost line to the Turbosmart BOV (already installed on the aluminum tubing) from the Holley manifold. Water for the cooler was supplied by the dyno, but additional power could be made available with ice water. After tuning on 100-octane race fuel, the supercharged 305 belted out some impressive numbers. Running a peak boost pressure of 10.2 psi at 6,000 rpm, the blown, Tuned Port Injection small-block produced 612 hp and 546 lb-ft of torque. Who says you can’t make power with a 305? CHP

2/20
1. How do you make power with a 305? Easy. Just add boost!

3/20
2. Our test mule started life as a simple LB9 TPI 305. Though taking a back seat to the larger 350, it was primarily the 305 that could be found slugging it out in the streets against the 5.0L Mustangs of the day.

4/20
3.The stock hydraulic roller stick was upgraded with a performance cam that offered a 0.570/0.565-inch lift split, a 218/224-degree duration split, and 113-degree LSA. This was a perfect little street cam for the 5.0L.

5/20
4. The stock, iron TPI heads were replaced by a set of as-cast TFS Super 23 175 alloy heads. The 175cc heads flowed amazingly well and were sized perfectly for the little 305.

6/20
5. Topping the TFS aluminum heads was a two-piece Holley Stealth Ram intake. The lower intake resembled a tunnel-ram equipped with injector bungs to allow the use of electronic fuel injection.

7/20
6. The box plenum bolted to the lower manifold using the supplied hardware and gaskets. The polished system was both visually impressive and considerably more powerful than the factory TPI.

8/20
7. Feeding the upper intake was a dual 58mm throttle body from Holley. The Stealth Ram and 58mm throttle body allowed us to keep the TPI look of the LB9.

9/20
8. Run with the new heads, cam, and intake, the modified 305 produced 372 hp at 5,900 rpm and 353 lb-ft of torque at 5,000 rpm.

10/20
9. After running the 305 in naturally aspirated trim, we installed the aluminum blower mounting bracket and tensioner assembly.

11/20
10. Next came the TorqStorm supercharger head unit. The blower bolted in place to the bracket using the supplied hardware. Note the use of a V-band clamp to allow easy orientation of the volute.

12/20
11. The TorqStorm kit featured a 3.25-inch (eight-rib) blower pulley. The eight-rib system combined with an efficient tensioner design eliminated any belt slippage during our testing.

13/20
12. Thanks to an efficient impeller design, the TorqStorm supercharger was able to support as much as 700 hp on the right application. This was more than enough for our street-oriented 305.

14/20
13. The kit also included this adapter hub/spacer to properly locate the crank pulley. The pulley was bolted to the stock damper using a combination of the center damper and three pulley mounting bolts.

15/20
14. With the hub in position, we bolted on the 8-inch aluminum crank pulley. Installation of the kit was very simple and straightforward.

16/20
15.After installation of the eight-rib belt, it was secured in place using the two-bolt tensioner system. This combination provided a repeatable boost curve run after run.

17/20
16. To spice things up we added this air-to-water intercooler. Since we had to design our own discharge tube anyway, we figured an intercooler was a good idea.

18/20
17. Though TorqStorm supplied a blow-off valve with their kit, our custom discharge tube was already equipped with a Race Port blow-off valve from Turbosmart.

19/20
18. Run on the dyno, the modified small-block showed just how well a 305 responds to boost. Equipped with the TorqStorm supercharger pumping out a peak of 10.2 psi, the 5.0L produced 612 hp at 6,000 rpm and 546 lb-ft of torque at 5,500 rpm.

20/20
19. Every engine responds to boost, even the 305. After the top-end modifications, the small-block produced 372 hp and 353 lb-ft of torque. Adding the TorqStorm centrifugal supercharger to the mix upped the ante to 612 hp and 546 lb-ft of torque. This thing would be seriously fun in a street/strip IROC.

keep in mind starting with a SBC , of a bit better list of components like a properly designed and built 383 -406 built with all forged components based on a static 8:1 compression with better set of 200cc-210cc heads and a better hydraulic roller cam like a crane 119661 or crower 00471 , larger 50-70 lb injectors,could rather easily hit 700-900 hp plus
going through this build using a 305 might seem impressive but its basically ignoring the true potential of the SBC engine as the slightly larger displacement and bore diameter allows larger valves much more efficient cylinder fill rates ETC.
I could not see building a 305 to make 600 hp when for very little additional expense you could build a 383 that would rather easily produce at least an additional 200 hp-400 hp, or put differently adding an aftermarket block, better forged internals better heads, and perhaps a larger air to surface inter-cooler , larger baffled oil pan a larger oil cooler,may add a couple thousand dollars but if your already spending $9-$11 k adding a couple extra $k surely would produce more impressive results
I rather enjoy the , local Saturday night "run what your brought"
racing, yes your limited to about a 13 second car,
but its still fun to watch because its mostly guys in street driven cars
what screws it up is theres always some guy that could run low 10 seconds with $5000 plus in computer controlled equipment,
that basically lets the car run the race, and click off boringly consistent runs
making the guys with basic street driven cars at a huge disadvantage in the long term.
when I first got my 1985 corvette it would consistently run about 14.5 seconds in its O.E.M. condition,
once I tweaked a few things and added a few parts .
consistent 13.3 second runs.
at this point I had a great deal of fun with the corvette.
yeah I decided to tweak the combo a bit, changed cams, several times, ported heads,added a 3200 rpm stall,
swapped to a custom ported and significantly modified stealth ram,much larger injectors, a new ignition,added slicks,
added a better 3" full length and well designed low restriction,exhaust ,
and low 11 second runs, with a 250 hp, wet nitrous kit ,
and getting told I could no longer race the car was a huge P.I.T.A.

related threads,
ignoring reading the links and sub-links is always a mistake

http://garage.grumpysperformance.com/index.php?threads/my-current-corvettes-383-combo.430/

http://garage.grumpysperformance.co...ive-are-the-stock-tpi-engine-components.1509/

http://garage.grumpysperformance.com/index.php?threads/how-big-a-fuel-pump-do-you-need.1939/

http://garage.grumpysperformance.co...n-jumping-in-with-both-feet.14918/#post-84132

http://garage.grumpysperformance.com/index.php?threads/ideal-tpi-build.12203/#post-76070

http://garage.grumpysperformance.co...ht-through-1985-vette-combo.14289/#post-72935

http://garage.grumpysperformance.com/index.php?threads/a-high-torque-406.12184/#post-68419

http://garage.grumpysperformance.com/index.php?threads/calculate-fuel-injector-size.1200/

http://garage.grumpysperformance.co...electing-a-torque-converter-stall-speed.1715/

http://garage.grumpysperformance.co...n-jumping-in-with-both-feet.14918/#post-84073

http://garage.grumpysperformance.com/index.php?threads/installing-a-big-block-chevy-in-a-c4.6/

http://garage.grumpysperformance.co...lap-on-factory-headers.3155/page-2#post-66721

http://garage.grumpysperformance.co...rger-intake-runners-l98-tpi.13785/#post-72541

http://www.blowerworks.net/

one major restriction to and TPI system running a stock MAF sensor is they are rather airflow restricted
due too both design and internal size, http://www.blowerworks.net/ sells custom 3" 3.5" and even 4" custom built MAF sensor designs,
obviously youll need a set of 30lb-50 lb injectors to keep up with the potential increased air flow and the controller that will also work with the custom parts

links to info that may help

https://www.themotorbookstore.com/c...MIrei9nJqr7gIVD4iGCh3orQayEAQYAiABEgJUMPD_BwE

http://www.larryselectricsite.com/downloads/tpiinstructions.pdf

https://howellefi.com/wp-content/up...t-or-LT1-Fuel-Injection-Harness-1985-1992.pdf

https://www.hotrodhardware.com/inde...d=7157/category_id=1579/mode=prod/prd7157.htm

https://www.ronfrancis.com/images/TP30-INST.pdf

http://www.jimsperformance.com/tpibuy.html

https://www.hotrodhandbooks.com.au/eBooks/TPI/TPI On Line-03-1.html
I found this info posted on a different web site

The minimal cross-sectional area of the head sets the maximum RPM potential and the head flow determines the maximum HP potential for a given engine. Intake flow equal to or greater than the head flow helps to insure it will not limit the potential HP capability of the head. An intake with a minimal cross-sectional area equal to or greater than the heads MCSA helps to insure it will not limit the RPM potential of the engine. HOWEVER, due to the physics involved, any intake runner length much over 3 on a SBC will start to reduce the RPM potential/capabilities. So, a longer runner will never be able to match the RPM potential of a short runner intake on the same engine.

When building a racing engine, as long as youre not exceeding the parts capabilities, RPM is king its easier to make higher HP numbers at higher RPMs. For racing, big heads, big cam, steep gears, and high stall speeds are part of the equation. However, the power under the curve (a factor of shift point, stall speed, and shift recovery RPM) is a major consideration as well. You see a lot of tunnel rams on racing engines with runner lengths greater than 3, so giving up some RPM potential for the extra power under the curve the longer runner length gives is not a bad thing even for a racing engine.

For a street engine, if youre not concerned about the idle speed and vacuum or the stall speed and gear ratio, you can treat the build similar to that of a racing engine. However, most street engines are a compromise of idle speed, vacuum, stall speed, and gearing the milder or the more compromised the build (smaller cams and lower stall speeds) the more critical that power under the curve becomes. Adding runner length increases midrange power but at some point it will take more power away from the top end than it can make up under the curve. That point will vary depending on different sized engines and with different transmissions.

I agree that the power band and cliff cant change much if using the stock GM type TPI runner systems especially on stock heads and even aftermarket heads and intakes (based on the GM style TPI) wont help much. However, while the runner length is the main contributor to the steep RPM and power drop off point, the diameter of the runner also affects the peak RPM capability for both TQ and HP.

Concerning the FIRST, the inherently bad runner to base and base to runner transition points of the stock type TPI intake systems have been eliminated with the FIRST and an unported base can flow over 300cfm. The amount of flow doesnt really help the limitation of the runner length, but does give the engine the potential to make a lot more power under the limit (more beneficial to larger engines).

The inside diameter (ID) of a stock FIRST runners is 1.75 (area 2.4). This targets peak torque around 4800rpm for a 350 (1200rpm more than a stock TPI), 4400rpm for a 383, and 4200rpm for a 406. The FIRSTs MCSA of the base (1.85 runner opening) is 2.69 and the runners can easily be opened up to that this bumps the peak TQ target RPM to around 4900 for a 383 and 4600 for a 406.

While the FIRSTs runner length (fractionally shorter than a stock TPI) still limits peak HP RPM and determines the tuned RPM band, due to the large ID of the FIRST runners it allows HP to peak at a higher RPM. The larger diameter of the runner also widens the tuned torque curve range. Another benefit of the larger diameter runners is you can select a cam to make peak TQ at the target RPM based on the runners MCSA. For instance, opening up the runners to 1.85 ID will target peak TQ for a 406 at 4600rpm. If you cam for that, its almost like adding an additional TQ peak, giving the sense of extending the tuned TQ curve even more.

For those wanting to crunch numbers, heres a calculator to find the area of a runner:
http://www.wallaceracing.com/chokepoint-rpm.php

Below is a good calculator that shows peak TQ RPM in regards to the area of the runner used:
https://rbracing-rsr.com/runnertorquecalc.html

This one (second input box) shows the relation between optimal runner length AND area (a function of diameter) based on engine size and cam duration.
http://www.wallaceracing.com/runnertorquecalc.php

While the FIRST kinda looks like a stock TPI, thats where the similarities end. The runners are cast with an INSIDE diameter of 1.75 and can be ported out to 1.92 INSIDE diameter. Thats an as cast FIRST runner on the far left, a set of stock TPI runners in the middle, and on the right is the FIRST runner ported to 1.92".

The entrance on the FIRST base is cast with a diameter of 1.847.

The intake flange is cast to a 1204 sized gasket, but inside the intake it curves down to a 1204. About an inch or so in, its comparable to a 1206 gasket and can be taken out to a 1207 sized gasket.

Ive run a fully ported TPI base (not welded) with fully ported and siamesed SLP runners, a box stock FIRST, and a StealthRam on the same engine in the same car only an intake and a little tuning for each were swapped. Same high 80-degee temps. The TPI/SLP shifted at 5500/5300 and ran low 13.0s to high 12.9s; the FIRST (box stock) shifted at 5800/5500 (ran the same times shifting at 6200/6000 though) and ran high 12.5s; the StealthRam shifted at 6400/6200 and ran low 12.6s. On this relatively mild 355 with a TH350, 3,000 stall, and 3.23 gears, I liked the FIRST better. It had a LOT more throttle response and was a lot more fun playing around on the street than the StealthRam. If it had been a 5 speed car with a bigger cam, or I had been running more stall speed and gearing, I probably would have preferred the StealthRam. So, whats best depends.

Here's some numbers from a May 1991 Popular Hot Rodding article.
9:1, 355, AFR 180 heads, mild hydraulic cam

RPM - FIRST - MiniRam - AZ Speed & Marine (Extrude base and Large Tube Runners)
2500 - 175 ---- 175 ----- 180
3000 - 237 ---- 222 ----- 238
3500 - 295 ---- 263 ----- 295
4000 - 350 ---- 300 ----- 325
4500 - 377 ---- 350 ----- 352
5000 - 388 ---- 375 ----- 350
5500 - 366 ---- 398 ----- 330

The FIRST made 443 TQ vs the Miniram's 395 TQ at 3500 rpm thats 48 lb/ft more
The FIRST made 460 TQ vs the Miniram's 394 TQ at 4000 rpm thats 66 lb/ft more

First Performance Center, LLC

Www.firstperfcenter.com

firstfuelinjection.com

With all that said, there is no question that a short/shorter runner intake will make more peak HP than a long/longer runner intake. If you cam, gear, and stall for the short/shorter runner it will always perform better at the drag strip compared to a long/longer runner intake. Close ratio manual transmissions also favor short/short runner intakes. However, its possible that a long/longer runner intake like the FIRST can deliver similar and sometimes better results at the drag strip when atop a milder combination with a wide ratio automatic transmission, lower than optimal stall speed converter, and lower numerical rear gears especially in heavier vehicles.

Hello, 91 corvette building a 383

Im building a 383 for my 91 Corvette, looking for info on different combination that will make this a quick street car that may see some track time.

garage.grumpysperformance.com

a couple hours of research reading threads can save you a ton of cash and weeks of wasted effort

http://garage.grumpysperformance.com/index.php?threads/the-new-215cc-vortec-heads.266/#post-75012

http://garage.grumpysperformance.co...c-gen-1-parts-compatibility.13439/#post-69800

http://garage.grumpysperformance.com/index.php?threads/vortec-edelbrock-tpi.11062/#post-49181

http://garage.grumpysperformance.co...-z51l9889-posted-much-of-this.823/#post-39088

http://garage.grumpysperformance.co...o-flow-firsts-tpi-intake-etc.1052/#post-37127

http://garage.grumpysperformance.co...-vortec-heads-and-other-heads.401/#post-34996

http://garage.grumpysperformance.com/index.php?threads/vortec-info.529/#post-27299

http://garage.grumpysperformance.co...-stock-tpi-engine-components.1509/#post-74581

http://garage.grumpysperformance.co...rger-intake-runners-l98-tpi.13785/#post-70716

http://garage.grumpysperformance.com/index.php?threads/ideal-tpi-build.12203/#post-59273

http://garage.grumpysperformance.com/index.php?threads/can-you-get-there-with-tpi.10494/#post-44299

Post in thread 'Hello, 91 corvette building a 383'

Jun 30, 2022

that's certainly easy to do if you have a reasonable budget and some mechanical skills and knowledge
the key in my experience is correctly matching the selected components.
the main issue is that the c4 corvette has HUGE performance potential but many of the OEM parts like the cylinder heads intake manifold and cam are very restrictive.
Id strongly suggest you look over and read a few threads links I'LL provide before you decide on the components you select,

personally I'd strongly suggest you start with the info in the links below, yeah,
it will take...

• Grumpy

Head Gasket Roughness (ra)

I've installed my heads now, getting ready for when the headers come back. I noticed the surface finish of the aluminum heads, they seemed to be very rough. But what is rough, how do you quantify roughness ??? Try telling your buddy what you mean when you say "it was very rough". The most...

garage.grumpysperformance.com

http://garage.grumpysperformance.com/index.php?threads/sbc-head-gasket-choice.11070/#post-79067

http://garage.grumpysperformance.com/index.php?threads/head-gasket-related.1859/#post-50617

http://garage.grumpysperformance.com/index.php?threads/head-gasket.10085/#post-39429

http://garage.grumpysperformance.co...ad-gasket-for-aluminum-heads.4403/#post-26317

http://garage.grumpysperformance.co...asket-bore-size-vs-bore-size.2681/#post-11603

 

[Strictly Attitude]

Good article but 100 octane fuel used also and agree sbc under boost could easy see 700hp

 

[Maniacmechanic1]

I will have the latest Article today Grumpy.
Its a really good engine bone stock and near 100 % reliable.
Just today I think BBC & Pontiac V8 for Real power.
Will stay together also without going broke.

 

[Maniacmechanic1]

I read Grumpy.
Done Poor Mans Hotrod style.
On a 2-bolt main block.
Not bad.
Nice Supercharger kit.
Shows the Technical fundamentals.
Thats important.

 

[Maniacmechanic1]

Turbos are real Finicky setting up.
I found that out 1st hand installing in the Race shop & with Crazy Ed in his garage.

 

[Grumpy]

this is interesting and probably a good deal compared to most kits I see, listed as a 500hp kit

http://store.summitracing.com/default.as...p;x=35&y=12

TFS-K314-500-450 is the part number. Summit has it for $1750

I find this kits info mis-leading in that they don,t go into the short block requirements NECESSARY to make the combo work
(youll need something like a 350-406 10.5:1 cpr shortblock)
Im running a set of TRICKFLOW heads on my 11:1 cpr 383 and Im making just under 500hp (N/A)( before the nitrous) but thats because I sellected to build an engine with a cam designed to maximize the potential of the 200hp nitrous system Im running, not the (N/A) results, theres nothing wrong with those TRICKFLOW HEADS that a mild port and bowl cleanup won,t fix, infact after that minimal work the heads slighly outflowed the 195cc AFR heads out of the box flow figures

Ive built several 383-406 sbc engines using

CROWERS #00471 hydrolic roller cam

http://www.crower.com/misc/cam_spec...=00471&x=28&y=4

First Performance Center, LLC

Www.firstperfcenter.com

firstfuelinjection.com

and CRANES

# 118551 solid roller cams

http://www.cranecams.com/?show=brow...rtType=camshaft

with 10.5-11:1 cpr that exceeded 500 N/A hp

they require a 3.73-4.56 rear gear and a 3000rpm stall converter, plus other mods to work correctly

theres many other combos that will get you a 500hp sbc, and you don,t necessarily need a roller cam or those cylinder heads either, BRODIX,AFR,DART PRO 1 and several hundred cams can get you there

example


http://airflowresearch.com/articles.htm then look in / SB Chevy Articles/AFR Article Archive