Hello, 91 corvette building a 383

91Vette

Member
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.
 

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
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.
Id strongly suggest you look over and read a few threads links ILL 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 some time and effort to read, but the info's based on dozens of c4 corvette engine builds and results,

AND it will save you weeks of work and prevent thousands of dollars wasted buying the wrong parts

the FIRST TPI intake, as its the best option on a TPI build BY FAR
as it kicks up torque noticeably between 2000rpm-5000rpm where you spend 90% plus of your time

the key here is matching the compression and cam timing(duration and lift) to the intakes sweet spot or power band
and matching the drive train gearing to the same rpm/power band

you want to match about the 2800 rpm-5900 rpm power band
this generally requires a 300 rpm stall converter and a 3,54:1-3.73:1 rear gear ratio and a cam having about a 230-238 intake duration at .050 lift





PDRM1966a.jpg
51000_bb697eb7ebe4189c2b45881e0a9534ca0a18789b.jpg



firstt.png


firstf.png


no other intake on a TPI wakes up a TPI like a FIRST INTAKE with great heads and a decent roller cam


ID read all the links and sub links, it will take days but save you lots of problems and save you lots of cash
firstp3.jpg

carefully matched, decent 195-225cc heads, you have lots of options


personally ID currently select brodix dragon slayer 225cc heads with dished 383 pistons to get to a 10:1 compression
the PROFILER 210cc or AFR 210cc are an option but ID go brodix here

yeah I can hear the screams now, from the "PORTS ARE TO BIG CROWD" personally Id prefer the over all flow characteristics of the brodix dragon slayer heads matched to the first tpi intake with any of the mentioned hydraulic roller cams in that proposed 383 for impresive power curves in the proposed rpm/power band in that 1991 vette.:like:

almost all current dyno testing shows larger valve, smaller combustion chamber and larger dish piston configs ,
on aluminum heads, with dual quench pads provide the best power curve and low detonation risk factors:nodding:



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

this matches the crower cam lift/duration, 383 displacement, first intake flow curve and BRODIX DRAGON SLAYER head flow potential
Ive had a great deal of success with the crower 00471 in similar 383-406 SBC builds


heres a very similar cam from lunati thats just a touch milder that might be about ideal

both require a 3000 rpm stall converter
and a cam like a crower 00471 with CROWER 1.6:1 STEEL ROLLER ROCKERS and a rocker stud girdle
and of course 36 lb-38 lb injectors and you transform a TPI corvette.


ID use a 7-8 quart baffled oil pan that fits your corvette, and Id strongly consider a larger aluminum radiator
and adding an oil cooler/trans cooler combo with a fan, 475-525 hp in a street drive-able easy to drive combo should be easily achieved

obviously ask questions as required














 
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Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
if you still want more power, add a super charger to that combo, and get an easy extra 160 plus more
hp, but that choice also mandate much deeper financial pockets, bigger brakes and a trans cooler and bigger radiator
if you think a super charger works well on a near stock TPI, you have no idea how it would boost power on the combo I listed with its far less restrictive intake and heads, but of course the injector size would need to be increased and the stock N/A compression dropped to near 8:1( the larger dished recessed pistons , with greater valve to piston clearance and lower compression, and 225cc port heads will work exceptionally well, especially if you build to be super charged)

s-l1600.jpg


I wish you were located within a few miles , (farmersville texas) so I could drop by and help out,
maybe supervise/consult and lend a hand, and make sure the build goes in a ;logical progression,
that looks like what will eventually be a very impressive build,
Id certainly start with the rear gear and converter swap,
followed by the long lock assembly with the FIRST TPI, intake, roller cam, and larger injectors etc.

these TPI builds , once done correctly are very satisfying , but the key is having the drive train, gearing compression etc match the intended power & rpm band and head flow etc.
 
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Indycars

Administrator
Staff member
Welcome to the forum from Oklahoma ! WelcomeToGrumpy's.gif

You should start a build thread for your engine in the "Engine Combos and Dynometer Database" section. Typically that's where most of them are.

When you get into the camshaft selection, I can run several simulations with Dynomation 6 so that you can see the differences. Caution ..... this requires some legwork on your part to come with flow numbers for the heads and camshaft specs, etc.

.
 

91Vette

Member
Thanks from Nebraska! I have a bunch of this info available for the cyl heads and the camshafts I have been thinking about using.
 

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
as I expected, I had someone ask me why I could possibly even suggest use of a 225cc port head on a TINY 383 SBC BUILD?
well as we gain experience you either use that experience to LEARN and improve or you ignore it and just keep making similar mistakes to those you've done in the past!
from what Ive seen you get significant gains in the mid and upper rpm ranges with those brodix heads over the typical 200cc and 210cc heads most guys use, on a serious street/strip combo sbc build with MINIMAL lower rpm power /torque losses , now I have to point out that if your cruising along at a steady 70mph, your using maybe 45-60hp to keep the car cruising at that steady speed, so youll never notice the potential loss of torque nor the minute or marginal loss of air flow port speeds, and once you stomp your gas petal to the flow your pushed back in the seat nearly instantly, and won't notice any loss in the power band for the first 1/2 second or so before the engine reaches its peak power, where theres actually some power gained.
lets look at the differences in port size/volume a second.

I see several guys suggest this afr head notice its about $120 more at $1950 a pair
it has a 2.110" H x 1.265 port opening (thats 2.669 sq inches) 10% smaller cross sectional area than the brodix heads below
195cc Street Head Flow Chart
.200.300.400.500.550
Int146201247275280
Exh119166197213218


I suggested this head(matched to the long runner TPI FIRST INTAKE who's long individual,
runner design more than compensates in maintaining air flow inertial mass and speeds in the mid and upper rpm ranges
Match Intake Port to FP 1206 (NOT A HUGE PORT SIZE) $1830
yet they come with larger 2.08 intake valves and stronger 7/16" rocker studs


Flow Chart cfm @ 28" H20



Part NumberValve Size0.2000.3000.4000.5000.6000.6500.700
DS 2252.080 Intake142212260287302302304
1.600 Exhaust115154183199204207210

find the closest intake gasket and use it as a guide to match the ports to as close as possible
COMMON SBC INTAKE GASKET PORTS
felpro # 1204=Port Size: 1.23" x 1.99"=2.448 sq inches
felpro # 1205=Port Size: 1.28" x 2.09"=2.67 sq inches
felpro # 1206=Port Size: 1.34" x 2.21"=2.96 sq inches
felpro # 1207=Port Size: 1.38" x 2.28"=3.146 sq inches
felpro # 1209=Port Size: 1.38" x 2.38"=3.28 sq inches
felpro # 1255 VORTEC=Port Size: 1.08" x 2.16"-2.33 sq inches
felpro # 1263=Port Size: 1.31" x 2.02"=2.65 sq inches
felpro # 1266=Port Size: 1.34" x 2.21"=2.96 sq inches
felpro # 1284 LT1=Port Size: 1.25 x 2.04''=2.55 sq inches
felpro # 1289 FASTBURN=Port Size: 1.30" x 2.31" 3.00 sq inches
 
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jac1892

Active Member
Guys how do you think the tpi from First, with the harness would work on my 82 crossfire corvette? The Renegade with the EBL, NEVER WORKED GOOD, cause I'm an old carb guy and not a tuner?? thanks
 

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
the FIRST intake would work just fine if you upgraded the cpu sensors, injectors and wire harness that controls the injectors to one out of a 1991 corvette, the first intake comes with the throttle body but you still need to correctly hook up the required sensors, injectors etc.
you could most likely get that from a corvette salvage yard


this thread and its related links and its contained sub links contain a huge amount of related useful info you can use







 
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jac1892

Active Member
Thanks, but do you have to be a tuner to get it to run, would it fit under the hood? That's also a pain in the butt, the hood clearance.
 

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
the TPI fits under the 1985 vette hood so I don't see it being an issue, with the 1982, but why not measure
you need a minimum of 9.25" inches under the hood, above the front edge of the block The least clearance point on the 1985 vette,
 

91Vette

Member
Grumpy, I like the idea of using the First intake and the larger Brodix heads, I would like to talk to you about this engine combination and go over a couple of ideas for it..
 

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
well post away, and everyone may learn something or at least have a few suggestions or point out potential flaws
 

91Vette

Member
Your suggestions sound good, however, I have already rebuilt the transmission and installed a 2600 stall converter. I have also installed new 3.54 rear gears, How if any, will these items affect the cam and heads you have been suggesting?

Do you build engines too? We are going to be in Dallas this October, do you want to build a 383 for me?
 

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
all my tools are still in storage and I have no shop as yet ,
as Im still working on my options here in texas , living with my son.
again talk to the cam vendor of choice

 
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91Vette

Member
Do I need to install a larger trans cooler with the 2600 converter or will the factory unit work just fine?
I am researching a radiator for the car as well.
 

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
install a transmission fluid heat gauge , as long as the trans fluid temps rarely exceed about 175F your fine, if the regularly exceed 190f I'D suggest you add a trans cooler


 

Indycars

Administrator
Staff member
You will not know for sure unless you measure the fluid temp in the pan, but I would suspect that you will need a cooler. Unless you plan on driving during the winter I would skip routing the fluid thru the radiator. There are several good coolers, but I've always used Derale and they are a quality unit. Go with a 1/2" lines or -8AN so there is no restriction to flow. Fans are going to help if you think there is a chance of much slow speed cruising.

Are you using a lock up torque converter ?
 

91Vette

Member
I just ordered a Derale cooler for it just to be sure. I have a lock up vigilante 2600 converter in the 700R4 trans.
Thanks for your help
 
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