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383 Stroker with FIRSTŪ intake swap

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Old Sep 17, 2021 | 01:17 PM
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Car: '18 Chev Camaro SS 1LE
Engine: LT1 6.2L
Transmission: T56
Axle/Gears: 3.91
383 Stroker with FIRSTŪ TPI

SOLD!!!

Last edited: 06-28-2025

See post #24 for anyone interested in tuning, I have attached my final .bin (S_AUJP v6.0) at post #24 or
https://www.thirdgen.org/forums/diy-...first-tpi.html
___________________________________________________________________________________________________________________

Thought I'd post my results on swapping the LB9 305TPI (1991) T5 with a 383 Stroker with FIRSTŪ TPI intake T56. Please feel free to ask questions in the comments. Hopefully that will help others interested in this kind of swap.

I posted some T/HP numbers at the end. This is not for argument or debate or bragging. It is just for comparison and to give an idea of what can be accomplished (give & take). There are many other set-up possible which would probably yield better numbers. That's not the point here. However, feel free to add comments on how it can be improved as long as it's TPI, not LSX nor carbureted and street friendly.

Engine is a 2018, 383 stroker GM crate SP383 Deluxe (GM part #19355672 assembled in Mexico):
  • Bore x Stroke (in.): 4.000 x 3.800
  • Block (P/N 88962513): Cast-iron with 4-bolt main caps
  • Crankshaft (P/N 12489436): Forged steel
  • Connecting Rods (P/N 12497624): Heavy-duty forged steel
  • Pistons (P/N 12499103): Hypereutectic aluminum
  • Camshaft Type (P/N 19210723): Hydraulic roller
  • Valve Lift (in.): .509 intake / .528 exhaust
  • Camshaft Duration (@.050 in.): 222° intake / 230° exhaust
  • Cylinder Heads (P/N 19300955): Fast Burn aluminum
  • 62-cc chambers
  • Valve Size (in.): 2.000 intake / 1.550 exhaust
  • Compression Ratio: 9.6:1
  • Rocker Arms (P/N 19210724): Aluminum roller style
  • Rocker Arm Ratio: 1.5:1
  • Recommended Fuel: Premium pump
  • Ignition Timing: Maximum of 32° total at 4000 rpm
  • Maximum Recommended rpm: 6000
  • Balanced: External
Induction system:
  • FIRSTŪ TPI Intake 835cfm, 71mm monoblade throttle body (was rated at in 2012)
  • FIC Bosch III Injector 32lbs/hr @43.5lbs (they reach max of 83%DC at WOT, 6000RPM, 13.4V)
  • ECM7730 with Moats emulator, S_AUJP v6.0, custom tune (by me!) SEE POST #24 for BIN https://www.thirdgen.org/forums/engi...ml#post6482729
  • Speed Density EFI, batchfire, port injection
  • All OE sensors. IAT relocated to airbox. Converted to heated O2 sensors on right bank.
  • Adjustable fuel pressure regulator, set at 43.5lbs (with vacuum disconnected)
  • Walbro 255lph fuel pump
  • OEM hard fuel lines with OE inline fuel filter
  • Pump gas 91 octane with Boostane = 98 octane
  • Custom 4in Specter cold air intake with zero restriction up to 6000 rpm
  • AFR at WOT is 12.4-12.8 depending on temperature
Ignition:
  • OE style HEI with remote coil, ECM controlled.
  • 30° maximum SA at WOT (no significant difference on chassis dyno between 32° and 28°)
  • Maximum SA reached at 3200RPM
  • No knock control
Exhaust:
  • Hedman headers #68470, shorty 3in collector, 1 5/8 primary (flanged modified to fit Vortec heads)
  • Custom Y-Pipe 2.5in dual to single 3in with high flow cat
  • Custom 3in single with Hooker exhaust dual pipes
  • No EGR
Transmission::
  • OE T5 bell housing and hydraulic clutch linkage
  • T56 Aftermarket #1386-000-011 with adapter plate / 2.97-2.07-1.43-1.00-0.80-0.62
  • TheGearBox Transmission Stage 2 Rebuild Kit
  • PRO 5.0 shifter with OE leather ****
  • McLeod Super Street Pro #75225
  • Speed sensor GM#10456087 (7teeth/21teeth)
  • 3in DOM custom drive shaft 1350 series https://driveshaftshop.com/
Accessories:
  • LB9 OE brackets
  • OE 105amp alternator, power steering pump, water pump, underdrive pulleys, no AC & no smog pump.
  • OE radiator
  • 180° F. Thermostat
  • OE dual electric fan, both ECM controlled
  • Cooling set up functions really good in my northern summer season (extreme max 95°F, might be an issue if racing or very hot weather like TX, AZ, FL, etc...)
  • EVAP system still in place
  • PCV system still in place with oil catch can
  • ME Wagner dual flow adjustable PCV valve
Mustagn Dyno Results:
334rwhp @ 4912rpm
412rwt @ 3803rpm

Estimated Dynojet results (for comparison):
360rwhp @ 4912rpm
445rwt @ 3803rpm

Flywheel estimated:
400hp @ 4900rpm
494t @ 3800rpm
BSFC 0.53 (12.8AFR / 32# / 83%DC / 13.4V)

GM rated with Chevrolet Performance Eliminator Vortec Intake Manifold, Holley 770cfm 4 barrel carburetor, 1.75" long tube headers:
435hp @ 5600rpm
445t @ 4600rpm

MotorTrend test:
446hp @ 5600rpm
448t @ 4600rpm
https://www.motortrend.com/how-to/te...t-performance/

Loss of peak HP due to TPI long runners = -10.3%

Car weights 3525lbs full gas tank. With me in it 3700lbs. On Toyo TQ drag radial 275/45R16 (16psi), at track, 3.89 Motive rear gear. Moser 9in, Eaton Detroit Truetrac, I get :

Best 1/4 mile (68Deg.F, 50% Humidity, 101 Baro & 321' elevation)
60' 1.853
330' 5.251
1/8 8.079
MPH 87.07
990' 10.426
1/4 12.527
Speed 110.63 mph

Best 1/4 mile trap speed:
111.88mph @ 64Deg.F
111.02mph @ 66Deg.F
110.63mph @ 68Deg.F
109.26mph @ 72Deg.F
108.50mph @ 81Deg.F (strong head wind!)

Best 60foot:
1.794

Estimated best potential 1/4 mile:
12.4 sec @ 112 mph

Estimated 1/4 mile with full engine potential (440HP with carburettor, no TPI) on this car:
12.1 sec @ 115 mph

For comparison with TGO member @my hemi who has similar set-up with AT with drag tires at track
https://www.thirdgen.org/forums/alte...k6ki2vediNhMiQ

60' 1.6
1/4 12.2 @ 111 mph

Also, the old modified LB9 with SLP cold air, TPI air foil, TB coolant by-pass, SLP underdrive pulleys, 1 5/8 shorty headers, Y pipe 2.75" with high flow cat to 3" single, hyperteck chip (160°Thermo). Dynojet results:
238rwhp @ 4500rpm
312rwt @ 3400rpm
Estimated:
270hp @ 4500rpm
354t @ 3400rpm
Best 1/4 mile
14.0 @ 98 mph
0-60 6.0sec

















Last edited by SbFormula; Jun 28, 2025 at 04:39 PM.
Old Sep 18, 2021 | 09:56 AM
  #2  
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From: Hurst, Texas
Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: 383 Stroker with FIRSTŪ intake swap

Originally Posted by SbFormula
Thought I'd post my results on swapping the LB9 305TPI (1991) 5MT to a 383 Stroker with FIRSTŪ intake 6MT. Please feel free to ask questions in the comments. Hopefully that will serve others interested in this kind of swap.

Engine is a 383 stroker GM crate SP383 Deluxe (GM part #19355672):
  • Bore x Stroke (in.): 4.000 x 3.800
  • Block (P/N 88962513): Cast-iron with 4-bolt main caps
  • Crankshaft (P/N 12489436): Forged steel
  • Connecting Rods (P/N 12497624): Heavy-duty forged steel
  • Pistons (P/N 12499103): Hypereutectic aluminum
  • Camshaft Type (P/N 19210723): Hydraulic roller
  • Valve Lift (in.): .509 intake / .528 exhaust
  • Camshaft Duration (@.050 in.): 222° intake / 230° exhaust
  • Cylinder Heads (P/N 19300955): Fast Burn aluminum;
  • 62-cc chambers
  • Valve Size (in.): 2.000 intake / 1.550 exhaust
  • Compression Ratio: 9.6:1
  • Rocker Arms (P/N 19210724): Aluminum roller style
  • Rocker Arm Ratio: 1.5:1
  • Recommended Fuel: Premium pump
  • Ignition Timing: 32° total at 4000 rpm
  • Maximum Recommended rpm: 6000
  • Balanced: External
Induction system:
  • FIRSTŪ Intake 835cfm
  • Bosch III Injector 32lbs/hr (they reach max of 80% duty at WOT)
  • ECM7730 with Moats emulator, S_AUJP v6.0, custom tune (by me!)
  • Adjustable fuel pressure regulator, set at 43.5lbs (with vacuum disconnected)
  • Walbro 255lph fuel pump
  • OEM hard fuel lines
  • Pump gas 91 octane with Boostane = 98 octane
  • Custom 4in cold air intake with zero restriction up to 6000 rpm
  • AFR at WOT is 12.6-13.0 depending on temperature
Ignition:
  • OE style HEI with remote coil
  • 30* maximum SA at WOT (no significant difference on dyno between 32* and 28*)
  • Maximum SA reached at 3200RPM
  • No knock control
Exhaust:
  • Hedman headers #68470, shorty 3in collector, 1 5/8 primary (flanged modified to fit Vortec heads)
  • Custom Y-Pipe 2.5in dual to single 3in with high flow cat
  • Custom 3in single with Hooker exhaust dual pipes
Accessories:
  • LB9 OE brackets
  • OE 100amp alternator, power steering pump, water pump, no AC, no smog pump.
  • OE radiator (function really good in my northern summer season, might be an issue if racing or very hot weather)
  • OE dual electric fan, both ECM controlled
  • EVAP system still in place
  • PCV system still in place with oil catch can
Car weights 3525lbs full gas tank. With me in it 3700lbs. On Nitto 555R drag radial, on the street, T56, 3.89 rear gear, I get:
60' 1.652
330' 5.196
1/8 8.135
MPH 84
1000' 10.636
1/4 12.708
Trap Speed 108
0-60mph 4.5

Mustagn Dyno Results:
334rwhp @ 4912rpm
412rwt @ 3803rpm
Converted to Dynojet:
360rwhp @ 4912rpm
445rwt @ 3803rpm
Flywheel estimated:
410hp @ 4912rpm
505t @ 3803rpm



Bet that is a hoot to drive with all the torque.
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Old Sep 18, 2021 | 11:21 AM
  #3  
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Re: 383 Stroker with FIRSTŪ intake swap

Originally Posted by Fast355
Bet that is a hoot to drive with all the torque.
Oh yeah!! Problem being: you get used to it and you want more lol. I was discussing pros and cons of Nitrous Oxide System with the performance shop. With the hypereutectic pistons, I'm worried I'll melt the engine or definitely shorten its life. Also, part of the drive train has its limits too.

Last edited by SbFormula; Sep 22, 2021 at 09:00 AM.
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Old Apr 16, 2022 | 06:34 AM
  #4  
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Re: 383 Stroker with FIRSTŪ intake swap

Nice build! I'm working on a similar project and I'm looking to purchase some shorty headers. What kind of modifications had to be done on your header flanges to work on your Vortec heads?
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Old Apr 19, 2022 | 06:32 PM
  #5  
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Re: 383 Stroker with FIRSTŪ intake swap

Originally Posted by carlos64030
What kind of modifications had to be done on your header flanges to work on your Vortec heads?
I reused the 1 5/8" primary shorty hedman headers #68470 that had been installed by the PO on the old LB9. One would think why the heck would you do that? Here are the reasons:
1) They fit perfectly with no clearance issue on my set-up
2) Zero cost at the time
3) Nothing available that would fit my single exhaust set-up for OEM M5 bellhousing and transmission crossmember/torque arm set-up
4) Optimal headers (1 3/4" primary for Vortec heads port) would have required expensive modifications to hydraulic clutch, bellhousing, crossmember/torque arm set-up and exhaust system.

I know they are not optimal for power. I get robbed some HP for sure. In my case it was irrelevant. For someone else it could be a big issue.

I decided to match the gasket to the headers and not the exhaust port. It seals perfectly using the Mr. Gasket copper #7150MRG. The picture shows the mismatch with bolt holes. That's the part that had to be modified on the gasket and headers flange. Using a carbide bit, the holes had to be elongated precisely so the gasket and flange would match. I used the gasket as a template so the exhaust ports would be "centered aligned". As you can see on the picture, the gasket is not optimal for the exhaust port shape. The installation was done with engine on stand so I could match everything correctly. Trying to do this with the engine in the engine bay is probably impossible.

IMO the best option is full on custom headers. That requires expertise and $$$$. If I ever find that kind of expertise around my neck of the woods, I will consider it. I don't know how much HP at the wheel it represents though.


Last edited by SbFormula; Apr 19, 2022 at 06:36 PM.
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Old Apr 19, 2022 | 06:45 PM
  #6  
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Car: Resto-Mod 1987 IROC-Z Clone
Engine: Alky fed L92 Vortec Twin-Turbo 6.8L
Transmission: My own built/ design 4L80M
Axle/Gears: Custom 12 bolt (4.10:1)
Re: 383 Stroker with FIRSTŪ intake swap

I really like your Thread so far, and I like your Engine Swap Project.

Now that most people are swapping to the Gen-III/ Gen-IV SBC Engine instead of the Gen-I SBC Engine...
I really like to see these Swaps!


I am in now way shape or form trying to diminish what you have done.
However I would like people to know that they can do a Swap like yours, for roughly the same budget...
And optimize the Build with a little research into Valve Events and Engine Performance...
And walk away with Power in the range of what you are making, up to another 100ish Horse-Power and 40 to 50 Ft/ Lbs of Torque.

People do not need to swap to a Gen-III/ Gen-IV SBC Engine, to have a 500 to 550 HP Engine that is very streetable.

Congrats on your Swap!

And again, it's great to see a Gen-I SBC Build!!!
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Old Apr 19, 2022 | 07:09 PM
  #7  
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Re: 383 Stroker with FIRSTŪ intake swap

Originally Posted by vorteciroc
I really like your Thread so far, and I like your Engine Swap Project.
Thanks for all the kind words.

Originally Posted by vorteciroc
I am in now way shape or form trying to diminish what you have done.
However I would like people to know that they can do a Swap like yours, for roughly the same budget...
And optimize the Build with a little research into Valve Events and Engine Performance...
And walk away with Power in the range of what you are making, up to another 100ish Horse-Power and 40 to 50 Ft/ Lbs of Torque.
Absolutely! They're are other combinations that would produce more HP with a 383 without being too loopy. The crate engine was a compromise, again not having access to local expertise made me go for the GM crate. However with a TPI intake, 500-550 peak HP could be difficult. For me, the TPI set-up was a must as I wanted to retain OE look. These guys did a great job on this one at 460HP:

http://www.rcsracingengines.com/Perf...evy%20EFI.html

Last edited by SbFormula; Apr 19, 2022 at 07:15 PM.
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Old Apr 19, 2022 | 10:18 PM
  #8  
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Car: Resto-Mod 1987 IROC-Z Clone
Engine: Alky fed L92 Vortec Twin-Turbo 6.8L
Transmission: My own built/ design 4L80M
Axle/Gears: Custom 12 bolt (4.10:1)
Re: 383 Stroker with FIRSTŪ intake swap

Awesome!
Thank you!


And Yes, you are correct, as the Intake-Manifold is a BIG restriction.
The TPI Configuration would have to go...
You are not going to see those High Power Numbers at Atmospheric Pressure.
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Old Apr 20, 2022 | 08:51 AM
  #9  
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Re: 383 Stroker with FIRSTŪ intake swap

Originally Posted by vorteciroc
And Yes, you are correct, as the Intake-Manifold is a BIG restriction.
The TPI Configuration would have to go...
Absolutely, the TPI was not designed for high rpm peak HP.

Here's an interesting chart comparing the SP383 Deluxe with the FIRSTŪ TPI Intake vs. GM Eliminator Vortec Intake Manifold with Holley 770cfm carburetor (what GM tested it with). For my needs, on the street, I find the TPI gives me more usable HP, specially in town when I want to keep the rev down. I never drag race and rarely do standing start accelerations. I like quick low rpm rolling accelerations. It keeps the law enforcement at bay. Getting to a stunting charge 0.1 or 0.2 sec faster is irrelevant lol. Just food for thought. It all depends on the application and what one wants. Also, what kind of HP/TQ the drive train and chassis are able to take.

Last edited by SbFormula; Dec 12, 2022 at 12:49 PM.
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Old Apr 20, 2022 | 03:17 PM
  #10  
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Re: 383 Stroker with FIRSTŪ intake swap

These GM 383s are awesome engines. I have the short block with AFR heads and a little milder cam than the SP383, and then a miniram intake.

it is freaking crazy how much torque it puts out.
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Old Apr 20, 2022 | 08:59 PM
  #11  
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Car: Resto-Mod 1987 IROC-Z Clone
Engine: Alky fed L92 Vortec Twin-Turbo 6.8L
Transmission: My own built/ design 4L80M
Axle/Gears: Custom 12 bolt (4.10:1)
Re: 383 Stroker with FIRSTŪ intake swap

I am not familiar with the "First Intake".

Are you referring to an Intake Manifold... or an Air Induction System?
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Old Apr 20, 2022 | 09:15 PM
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Re: 383 Stroker with FIRSTŪ intake swap

https://firstfuelinjection.com
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Old Apr 21, 2022 | 12:20 AM
  #13  
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Re: 383 Stroker with FIRSTŪ intake swap

Originally Posted by Tuned Performance
Awesome, Thank you!
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Old Apr 21, 2022 | 06:48 AM
  #14  
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Re: 383 Stroker with FIRSTŪ intake swap

However with a TPI intake, 500-550 peak HP could be difficult.
its been done but it aint easy. Lots of rework into the base and runners

​​​​​​​https://www.thirdgen.org/forums/tpi/...be-runner.html
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Old Apr 21, 2022 | 10:51 AM
  #15  
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Re: 383 Stroker with FIRSTŪ intake swap

Originally Posted by vorteciroc
I am not familiar with the "First Intake".

Are you referring to an Intake Manifold... or an Air Induction System?
I should have written "FIRSTŪ TPI Intake"
I corrected some of the thread but can't correct the title.
I see someone gave you the link https://firstfuelinjection.com/
Cheers


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Old Apr 23, 2022 | 05:37 PM
  #16  
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Transmission: My own built/ design 4L80M
Axle/Gears: Custom 12 bolt (4.10:1)
Re: 383 Stroker with FIRSTŪ intake swap

Your Cylinder Heads have raised Exhaust-Ports...
There should be a Gasket Set that is intended to fit.

Raised Intake or Exhaust Ports are much more common in Higher Performance Heads.
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Old Apr 23, 2022 | 07:58 PM
  #17  
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Re: 383 Stroker with FIRSTŪ intake swap

Originally Posted by vorteciroc
Your Cylinder Heads have raised Exhaust-Ports...
There should be a Gasket Set that is intended to fit.

Raised Intake or Exhaust Ports are much more common in Higher Performance Heads.
Yes! Raised port 0.200". Gasket Fel-Pro #1470. Problem with my set-up is the vortec gasket would not seal my headers. And "bolt-on" headers that would fit my set-up are not available. For this swap, if one wants to maximize the exhaust, one needs long tube headers with custom exhaust which most likely requires to do away with OE hydraulic clutch/fork and a need for custom transmission crossmember to accept long tube headers.

Here's what GM Performance recommends: "The SP383 High Performance engine should be installed with a pair of high performance headers for maximum performance. The headers used during development of the SP383 had 1.75" diameter primary tubes. Primary tubes were approximately 32.00" in length and had 3.00" diameter collectors. Using a similar combination in your application, along with a performance exhaust system with a balance tube (“H” pipe) and low restriction mufflers, will provide you with optimum performance from your SP383 High Performance engine."
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Old Apr 25, 2022 | 07:27 PM
  #18  
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Re: 383 Stroker with FIRSTŪ intake swap

Which (Brand/ Model/ Part Number) "Vortec" exhaust gaskets did you try?

If the dimensions of the Gasket were correct or even close...
And they did not seal well...
Some of these Gaskets (depending on what material they are made of) can be doubled-up to seal better.
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Old Apr 25, 2022 | 07:52 PM
  #19  
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Re: 383 Stroker with FIRSTŪ intake swap

Originally Posted by vorteciroc
Which (Brand/ Model/ Part Number) "Vortec" exhaust gaskets did you try?

If the dimensions of the Gasket were correct or even close...
And they did not seal well...
Some of these Gaskets (depending on what material they are made of) can be doubled-up to seal better.


The Fel-Pro 1470. But I have to explain better lol. I was worried, the gasket (#1470) would not seal properly by looking at the mock-up. Those headers were not made to fit the Fast burn heads. The headers flange has a round matting surface were the round copper gasket fits nicely. Since the headers flange was already interfering with the port exhaust anyway, I decided to play safe and go with the round copper gasket. Would the #1470 gasket had sealed? Maybe. Would I had taken a chance? No. Doubling-up could have created a bolt length problem and also clearance issue. Let's say, I went with the easy and safe route the day I had to make the decision... among many many other decisions.

Last edited by SbFormula; Apr 25, 2022 at 07:57 PM.
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Old Apr 25, 2022 | 08:17 PM
  #20  
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Car: Resto-Mod 1987 IROC-Z Clone
Engine: Alky fed L92 Vortec Twin-Turbo 6.8L
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Re: 383 Stroker with FIRSTŪ intake swap

Unless your Header Flanges are perfectly straight (which most of the time they are not) the Copper Gaskets will not seal well.

"Dead-Soft" Aluminum Gaskets are amazing...
Otherwise I would definitely try a different Material than Copper (no plain Paper either; they blow-out very easily).
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Old Aug 19, 2022 | 10:42 PM
  #21  
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Re: 383 Stroker with FIRSTŪ intake swap

GREAT WRITE UP!!!
I am getting ready to drop my sp350/357 crate/FIRST TPI intake and wondering if ya used '6in. or '8in. external Harmonic balacer?
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Old Aug 20, 2022 | 02:57 PM
  #22  
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Re: 383 Stroker with FIRSTŪ intake swap

Originally Posted by jasper21
GREAT WRITE UP!!!
I am getting ready to drop my sp350/357 crate/FIRST TPI intake and wondering if ya used '6in. or '8in. external Harmonic balacer?
Thanks!
8in, GM part# 12498008, https://www.summitracing.com/parts/nal-12498008
It came installed with the GMP crate engine.
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Old Oct 18, 2022 | 07:25 AM
  #23  
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Re: 383 Stroker with FIRSTŪ intake swap

Originally Posted by vorteciroc
Unless your Header Flanges are perfectly straight (which most of the time they are not) the Copper Gaskets will not seal well.
I've heard that argument many times. Even have a local guy who had that problem when he was flooring it. He could hear the exhaust whistling. I guess I'm lucky on this one. Every time I inspect, there is no evidence on any leaks. And I do inspect on regular basis top to bottom using my hoist.
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Old Oct 18, 2022 | 07:35 AM
  #24  
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Re: 383 Stroker with FIRSTŪ intake swap

Here's the final .bin (S_AUJP v6.0) for my set-up.
Many, many, many hours went into this with years of continuous learning.

https://www.thirdgen.org/forums/diy-...first-tpi.html
Attached Files
File Type: bin

Last edited by SbFormula; Aug 24, 2023 at 08:06 AM.
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Old Oct 25, 2022 | 05:32 PM
  #25  
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Re: 383 Stroker with FIRSTŪ intake swap

A++ outstanding information on before and after results. Excellent build and enjoyed reading very much!
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Old Feb 25, 2023 | 10:04 PM
  #26  
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Engine: 350 tpi supercharged and a 383 stro
Transmission: Both 700r4s
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Re: 383 Stroker with FIRSTŪ TPI

Originally Posted by SbFormula
Last edited: 02-18-2023

Thought I'd post my results on swapping the LB9 305TPI (1991) T5 with a 383 Stroker with FIRSTŪ TPI intake T56. Please feel free to ask questions in the comments. Hopefully that will help others interested in this kind of swap.

I posted some T/HP numbers at the end. This is not for argument or debate or bragging. It is just for comparison and to give an idea of what can be accomplished (give & take). There are many other set-up possible which would probably yield better numbers. That's not the point here. However, feel free to add comments on how it can be improved as long as it's TPI, not LSX nor carbureted and street friendly.

Engine is a 2018, 383 stroker GM crate SP383 Deluxe (GM part #19355672 assembled in Mexico):
  • Bore x Stroke (in.): 4.000 x 3.800
  • Block (P/N 88962513): Cast-iron with 4-bolt main caps
  • Crankshaft (P/N 12489436): Forged steel
  • Connecting Rods (P/N 12497624): Heavy-duty forged steel
  • Pistons (P/N 12499103): Hypereutectic aluminum
  • Camshaft Type (P/N 19210723): Hydraulic roller
  • Valve Lift (in.): .509 intake / .528 exhaust
  • Camshaft Duration (@.050 in.): 222° intake / 230° exhaust
  • Cylinder Heads (P/N 19300955): Fast Burn aluminum
  • 62-cc chambers
  • Valve Size (in.): 2.000 intake / 1.550 exhaust
  • Compression Ratio: 9.6:1
  • Rocker Arms (P/N 19210724): Aluminum roller style
  • Rocker Arm Ratio: 1.5:1
  • Recommended Fuel: Premium pump
  • Ignition Timing: Maximum of 32° total at 4000 rpm
  • Maximum Recommended rpm: 6000
  • Balanced: External
Induction system:
  • FIRSTŪ TPI Intake 835cfm, 71mm monoblade throttle body (was rated at in 2012)
  • FIC Bosch III Injector 32lbs/hr @43.5lbs (they reach max of 83%DC at WOT, 6000RPM, 13.4V)
  • ECM7730 with Moats emulator, S_AUJP v6.0, custom tune (by me!)
  • Speed Density EFI, batchfire, port injection
  • All OE sensors. IAT relocated to airbox. Converted to heated O2 sensors on right bank.
  • Adjustable fuel pressure regulator, set at 43.5lbs (with vacuum disconnected)
  • Walbro 255lph fuel pump
  • OEM hard fuel lines with OE inline fuel filter
  • Pump gas 91 octane with Boostane = 98 octane
  • Custom 4in Specter cold air intake with zero restriction up to 6000 rpm
  • AFR at WOT is 12.6-13.0 depending on temperature
Ignition:
  • OE style HEI with remote coil, ECM controlled.
  • 30° maximum SA at WOT (no significant difference on chassis dyno between 32° and 28°)
  • Maximum SA reached at 3200RPM
  • No knock control
Exhaust:
  • Hedman headers #68470, shorty 3in collector, 1 5/8 primary (flanged modified to fit Vortec heads)
  • Custom Y-Pipe 2.5in dual to single 3in with high flow cat
  • Custom 3in single with Hooker exhaust dual pipes
  • No EGR
Transmission::
  • OE T5 bell housing and hydraulic clutch linkage
  • T56 Aftermarket #1386-000-011 with adapter plate / 2.97-2.07-1.43-1.00-0.80-0.62
  • TheGearBox Transmission Stage 2 Rebuild Kit
  • PRO 5.0 shifter with OE leather ****
  • Centerforce dual friction clutch #DF161056
  • Speed sensor GM#10456087 (7teeth/21teeth)
  • 3in DOM custom drive shaft 1350 series https://driveshaftshop.com/
Accessories:
  • LB9 OE brackets
  • OE 105amp alternator, power steering pump, water pump, underdrive pulleys, no AC & no smog pump.
  • OE radiator
  • 180° F. Thermostat
  • OE dual electric fan, both ECM controlled
  • Colling set up functions really good in my northern summer season (extreme max 95°F, might be an issue if racing or very hot weather like TX, AZ, FL, etc...)
  • EVAP system still in place
  • PCV system still in place with oil catch can
Mustagn Dyno Results:
334rwhp @ 4912rpm
412rwt @ 3803rpm

Estimated Dynojet results (for comparison):
360rwhp @ 4912rpm
445rwt @ 3803rpm

Flywheel estimated:
400hp @ 4900rpm
494t @ 3800rpm
BSFC 0.53 (12.8AFR / 32# / 83%DC / 13.4V)

GM rated with Chevrolet Performance Eliminator Vortec Intake Manifold, Holley 770cfm 4 barrel carburetor, 1.75" long tube headers:
435hp @ 5600rpm
445t @ 4600rpm

MotorTrend test:
446hp @ 5600rpm
448t @ 4600rpm
https://www.motortrend.com/how-to/te...t-performance/

Car weights 3525lbs full gas tank. With me in it 3700lbs. On Toyo TQ drag radial 275/45R16, on the street, 3.89 Motive rear gear. Moser 9in, Eaton Detroit Truetrac, I get @ 77Deg.F 40% Humidity 103 Baro (sea level):

Best 1/4 mile
60' 1.652
330' 5.141
1/8 8.019
MPH 86
1000' 10.435
1/4 12.456
Speed 111 mph
0-60mph 4.5

For comparison with TGO member @my hemi who has similar set-up with AT
https://www.thirdgen.org/forums/alte...k6ki2vediNhMiQ

60' 1.671___1.683
330' 5.026___5.057
1/8 7.847___7.879
MPH 87___87
1000' 10.283___10.313
1/4 12.350___12.376
Speed 109___109 mph

Also, the old modified LB9 with SLP cold air, TPI air foil, TB coolant by-pass, SLP underdrive pulleys, 1 5/8 shorty headers, Y pipe 2.75" with high flow cat to 3" single, hyperteck chip (160°Thermo). Dynojet results:
238rwhp @ 4500rpm
312rwt @ 3400rpm
Estimated:
270hp @ 4500rpm
354t @ 3400rpm
Best 1/4 mile
14.0 @ 98 mph
0-60 6.0sec

UPDATE: For anyone interested in tuning, I have attached my final .bin (S_AUJP v6.0) at post #24 or https://www.thirdgen.org/forums/diy-...first-tpi.html


https://youtu.be/vzCfPr2yKU4










https://youtu.be/HD0QQd_g_MU

What do you shift at.. we found ours is only shifting at 5000 rpms leaving a little on the table she managed a best of 12.2 at 110 I want her to shift at 5500 rpms I think she'll pick up a .1 or .2 we'll be going out in a few months hopefully...
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Old Feb 26, 2023 | 07:22 AM
  #27  
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Re: 383 Stroker with FIRSTŪ TPI

Originally Posted by my hemi
What do you shift at.. we found ours is only shifting at 5000 rpms leaving a little on the table she managed a best of 12.2 at 110 I want her to shift at 5500 rpms I think she'll pick up a .1 or .2 we'll be going out in a few months hopefully...
Hey ​​​​@my hemi !

Good question

I believe, the theory is to maximize average HP on each gear (the area under the curve). So your shift points should be based on your engine HP curve, but also transmission gear ratios. I have a T56, you have an AT. So it might be hard to compare. On my 1st to 2nd to 3rd to 4th gear, it drops just over 1800RPM each time. So I did the math and I have to shift at 6000RPM (engine max RPM) on 1st-2nd and 3rd. From 4th to 5th it drops 1100RPM and from 5th to 6th it drops 1200RPM. So on the 4th and 5th there is no need to rev pass 5500RPM.

Even if HP starts decreasing pass 5000RPM, there is less HP loss from 5000 to 6000RPM compare to the HP loss of shifting lower than 6000RPM. It's simple math. Plus I get the benefit of lower gear.

Example (all things being equal): if I was to shift at 5000RPM on 3rd gear, it would drop to 3500RPM instead of 4200RPM on 4th gear. I would lose ave HP from 5000 to 6000RPM on 3rd gear (404 to 383HP) and gain ave HP from 3500 to 4200RPM on 4th gear (330 to 386HP). Simplified way of calculating the delta is using area of right triangle + area of rectangle. Let's say 25HP = 25 units and 50RPM = 50 units, basically 1 for 1.

Loss of HP on 3rd gear
Right triangle [((404-383)/25) * ((6000-5000)/50)]/2 = 8.4
Rectangle [(383/25) * ((6000-5000)/50)] = 306.4
Total loss 314.8 units

Gain of HP on 4th gear
Right triangle [((386-350)/25) * ((4200-3500)/50)]/2 = 10.1
Square [(350/25) * ((4200-3500)/50)] = 196.0
Total gain 206.1 units

Delta = minus 108.7 units

So I would rather push on the 3rd gear up to 6000RPM and gain 108.7 units of power combine with lower gear.

For your AT, you'd have to see what can be done. Have no clue of your gear ratios and how AT can be adjusted. Not my cup of tea. I would say if it shifts at 5000RPM, it appears low, but it all depends where it lands. If you take my HP curve for instance. If it shifts at 5000RPM and lands around 4200RPM, there would be no gain, at first glance, in having it shift at 5500RPM and land at 4600RPM (the drop is accentuated the higher the rpm is). Maybe a gain in working longer on a lower gear though.

If you compare your 1/4 mile to mine, you have faster ET because mine is almost a rolling start, but I get faster trap speed. So I would say, you are leaving HP on the table.

Check this calculator online. It's a different explanation but the same principles. It uses torque numbers with gear ratios. It pretty much confirmed my own calculations.

https://glennmessersmith.com/shiftpt.html

Hope this helps. Probably more info on TGO about AT shift points with high performance TPI.


Last edited by SbFormula; Feb 26, 2023 at 07:54 AM.
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Old Feb 26, 2023 | 10:42 AM
  #28  
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Car: A few things lol
Engine: 350 tpi supercharged and a 383 stro
Transmission: Both 700r4s
Axle/Gears: 3.23s and 3.54s
Re: 383 Stroker with FIRSTŪ intake swap

We have a 3.54 gear ratio the car imo i think will benefit from a higher shift point from 2nd to 3rd car imo still has more on top then 5000 rpms.. lol only true way to find out will be trial and error on the strip..
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Old Feb 26, 2023 | 10:52 AM
  #29  
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Re: 383 Stroker with FIRSTŪ intake swap

Originally Posted by my hemi
We have a 3.54 gear ratio the car imo i think will benefit from a higher shift point from 2nd to 3rd car imo still has more on top then 5000 rpms.. lol only true way to find out will be trial and error on the strip..
Sure! Nothing like real world testing.

Remember, the rear gear ratio does not affect the drop in RPM between transmission gear (shift).
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Old Feb 26, 2023 | 11:43 AM
  #30  
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Car: A few things lol
Engine: 350 tpi supercharged and a 383 stro
Transmission: Both 700r4s
Axle/Gears: 3.23s and 3.54s
Re: 383 Stroker with FIRSTŪ intake swap

Problem is the 700r4 has such a low 1st gear then it drops alot to second then 3rd..the transmission is setup uses a governor to make it shift at max rpm unfortunately it's set to a stock 305 or 350 tpi which we all now doesn't make much power past 4500 rpm so with the Change in the motor now with the bigger cu inch.. cam etc the stock shift points dont cut it imo..so for it to run as decent as it is only tells me it definitely has more in it..just sucks it can't be adjusted like modern day car thru the computer the 700r4 uses a TV cable and that governor only way it to manually shift it which is our next time out.
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Old Mar 1, 2023 | 12:07 PM
  #31  
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Re: 383 Stroker with FIRSTŪ intake swap

What intake gasket are you using with your First TPI and the fastburn heads? i see you are using the traditional 6 per side bolt pattern vs the vortec... i am doing a similar build and wondering on the intake gasket

thanks and great looking build
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Old Mar 1, 2023 | 05:39 PM
  #32  
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Re: 383 Stroker with FIRSTŪ intake swap

Originally Posted by alan91z28
What intake gasket are you using with your First TPI and the fastburn heads? i see you are using the traditional 6 per side bolt pattern vs the vortec... i am doing a similar build and wondering on the intake gasket

thanks and great looking build
Thank you!

I used the FIRST TPI intake gasket. I believe it's a 1204 style but made to fit traditional or Vortec. Check with Ken at https://firstfuelinjection.com/



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Old Dec 2, 2023 | 09:48 AM
  #33  
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Axle/Gears: 3.91
Re: 383 Stroker with FIRSTŪ intake swap

UPDATE After 3900miles, 5 years (summers)

As you can see, I don't drive it much. Around 800 miles per summer. It took a while to fix a drivetrain vibration, so the car sat more than it should have been. Vibration is finally fixed (https://www.thirdgen.org/forums/tran...s-another.html).

This summer, I was finally able to take it to an official dragstrip. It performed as expected with a 3700lbs, 400HP street car.

All in all, I am very satisfied with the set-up. It does what it was intended to do. It performs really well on the street but lacks traction and top end at the dragstrip. Nothing surprising as the engine is rated at 6000rpm max and the TPI is restrictive. If you want it to perform at the dragstrip, you need a carburetor and more traction. The main thing is the whole set-up stays true to the "Formula" concept and TPI era. If not, well, I would have gone LS for sure.

The engine is low maintenance. The spark plugs look good (inspected every spring) and compression is equal on all 8 at around 185psi. Oil pressure is always normal using Royal Purple 10W30. I'm not worried. No leaks, no over heating, no weird noises. The valvetrain is a bit chatty, but it was like this from factory. Nothing over the top. No exhaust leaks. Engine warms up quickly on start-ups, way quicker than OEM. I like that.

The low-mid range rpm torque combined with the throttle quick response is phenomenal. I don't feel it as much because I'm used to it now. Still makes me laugh every time. If I take a passenger on, it instantly brings a smile to their face. Car feels fast and intimidating.

Here's a statement from a 480 HP EV owner who rode shotgun with me: "you can get that much fun with an EV"... as he was grinning from ear to ear. The guy is a race car driver!!!!

In the end, it's not all about numbers... and we are way too hard on ourselves when it comes down to evaluating our build.





Last edited by SbFormula; Feb 15, 2025 at 06:28 AM.
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Old Dec 2, 2023 | 04:51 PM
  #34  
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Re: 383 Stroker with FIRSTŪ intake swap

Great update... sounds like you are quite happy and having great fun with your set-up... I am just finishing a FIRST install and looking forward to it based on your reports!
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Old Apr 26, 2024 | 08:42 PM
  #35  
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Re: 383 Stroker with FIRSTŪ intake swap

Originally Posted by alan91z28
I am just finishing a FIRST install and looking forward to it based on your reports!
@alan91z28 , have you finished your FIRST install?
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Old Apr 27, 2024 | 08:13 PM
  #36  
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Re: 383 Stroker with FIRSTŪ intake swap

Originally Posted by SbFormula
@alan91z28 , have you finished your FIRST install?
yes i have and i just over the last couple weeks have gotten it fired up and about 200 miles on it... have it tuned in pretty reasonable and i am lovin' it!

see my thread below starting around post 126
https://www.thirdgen.org/forums/engi...t-coupe-3.html
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Old Jun 17, 2024 | 05:11 PM
  #37  
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Re: 383 Stroker with FIRSTŪ intake swap

First summer drag!

60' 1.794
330' 5.232
660' 8.107
MPH 85.42
990' 10.498
1/4 12.639
108.5 mph

We had a good head wind that dropped trap speed. Car can do 112mph on a good day. I improved my 60 foot by almost 2/10!!! That tells me, car has potential of 12.4 @ 112mph. If I ever get there, I'll gladly update. Until then it's all "talk".

Will also have an update on engine oil consumption. I believe it has been resolved but I need to put more miles on it to confirm it.


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Old Jun 18, 2024 | 08:21 AM
  #38  
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Car: A few things lol
Engine: 350 tpi supercharged and a 383 stro
Transmission: Both 700r4s
Axle/Gears: 3.23s and 3.54s
Re: 383 Stroker with FIRSTŪ intake swap

Originally Posted by SbFormula
First summer drag!

60' 1.794
330' 5.232
660' 8.107
MPH 85.42
990' 10.498
1/4 12.639
108.5 mph

We had a good head wind that dropped trap speed. Car can do 112mph on a good day. I improved my 60 foot by almost 2/10!!! That tells me, car has potential of 12.4 @ 112mph. If I ever get there, I'll gladly update. Until then it's all "talk".

Will also have an update on engine oil consumption. I believe it has been resolved but I need to put more miles on it to confirm it.

https://youtu.be/Dl0cUv9uIGw?si=3CI0mCge1kcJatOi
im.sure there is more In it ours shifting at 5000 rpms did 12.2 at 110 on a soft launch with 1.6x 60fts so you'll get low 12s with more seat time.
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Old Aug 23, 2024 | 08:14 PM
  #39  
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Re: 383 Stroker with FIRSTŪ intake swap

OIL CONSUMPTION UPDATE

Well, it's solved! The problem was the PCV valve. I used the PCV valve recommended in the GM SP383 engine manual, PCV valve #6487779. I guess it's problematic. I installed the Wagner Dual Flow Adjustable PCV Valve #DF-17 following the instructions carefully. Problem solved. After 400 miles, barely any oil used. I would have more than half a quart gone with the GM PCV valve at that milage. Interesting that the catch can was not "catching" the oil.

Thanks to @EDGE for his suggestion and guidance. He had gone through the same problem.

https://mewagner.com/?p=444

Last edited by SbFormula; Aug 23, 2024 at 08:17 PM.
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Old Aug 24, 2024 | 09:46 AM
  #40  
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Car: A few things lol
Engine: 350 tpi supercharged and a 383 stro
Transmission: Both 700r4s
Axle/Gears: 3.23s and 3.54s
Re: 383 Stroker with FIRSTŪ intake swap

Originally Posted by SbFormula
OIL CONSUMPTION UPDATE

Well, it's solved! The problem was the PCV valve. I used the PCV valve recommended in the GM SP383 engine manual, PCV valve #6487779. I guess it's problematic. I installed the Wagner Dual Flow Adjustable PCV Valve #DF-17 following the instructions carefully. Problem solved. After 400 miles, barely any oil used. I would have more than half a quart gone with the GM PCV valve at that milage. Interesting that the catch can was not "catching" the oil.

Thanks to @EDGE for his suggestion and guidance. He had gone through the same problem.

https://mewagner.com/?p=444
I solved our issues with a catch can tied into the pcv system like modern cars use works perfectly.
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Old Aug 25, 2024 | 10:41 AM
  #41  
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Re: 383 Stroker with FIRSTŪ intake swap

Originally Posted by my hemi
I solved our issues with a catch can tied into the pcv system like modern cars use works perfectly.
I surely can appreciate your solution. In my case, I wanted to prevent the oil from exiting the engine in the first place, since it was at an excessive rate.

@EDGE had same problem. His catch can would fill quickly. The M/E Wagner Dual Flow Adjustable PCV valve solved the problem for good.

Peace
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Old Aug 25, 2024 | 03:02 PM
  #42  
my hemi's Avatar
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From: NJ
Car: A few things lol
Engine: 350 tpi supercharged and a 383 stro
Transmission: Both 700r4s
Axle/Gears: 3.23s and 3.54s
Re: 383 Stroker with FIRSTŪ intake swap

Originally Posted by SbFormula
I surely can appreciate your solution. In my case, I wanted to prevent the oil from exiting the engine in the first place, since it was at an excessive rate.

@EDGE had same problem. His catch can would fill quickly. The M/E Wagner Dual Flow Adjustable PCV valve solved the problem for good.

Peace
Got ya we never had much oil in the intake I noticed a light film noting major thru a catch can on never looked backed...

And my hemis all run catch cans all modern cars suck oil into the intakes just the Nature of the beast..
So I figure easy solution for us throw one on worked great.
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Old Aug 26, 2024 | 07:59 AM
  #43  
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Car: 86 Trans Am/85 K5 Jimmy
Engine: 406 FIRST/350 TPI
Transmission: TKO 600/700R4
Axle/Gears: 9Bolt/10Bolt front & back
Re: 383 Stroker with FIRSTŪ intake swap

If I can't solve my oil consumption with a better baffle method I am trying & adding a catch can then I will be probably be purchasing that valve...but man that is one expensive PCV Valve.
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Old Aug 26, 2024 | 08:28 AM
  #44  
my hemi's Avatar
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From: NJ
Car: A few things lol
Engine: 350 tpi supercharged and a 383 stro
Transmission: Both 700r4s
Axle/Gears: 3.23s and 3.54s
Re: 383 Stroker with FIRSTŪ intake swap

Originally Posted by dabomb6608
If I can't solve my oil consumption with a better baffle method I am trying & adding a catch can then I will be probably be purchasing that valve...but man that is one expensive PCV Valve.
catch can will work just fine.. dont need anything fancy imo.. just go look at all the hemi motors, LS motors they all run a catch can system..
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Old Aug 26, 2024 | 08:29 AM
  #45  
my hemi's Avatar
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From: NJ
Car: A few things lol
Engine: 350 tpi supercharged and a 383 stro
Transmission: Both 700r4s
Axle/Gears: 3.23s and 3.54s
Re: 383 Stroker with FIRSTŪ intake swap

Originally Posted by dabomb6608
If I can't solve my oil consumption with a better baffle method I am trying & adding a catch can then I will be probably be purchasing that valve...but man that is one expensive PCV Valve.
And our pcv valve is ran thru the catch can so its still very functional like the factory one..
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Old Aug 26, 2024 | 09:54 AM
  #46  
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From: Marion, IL
Car: 86 Trans Am/85 K5 Jimmy
Engine: 406 FIRST/350 TPI
Transmission: TKO 600/700R4
Axle/Gears: 9Bolt/10Bolt front & back
Re: 383 Stroker with FIRSTŪ intake swap

Originally Posted by my hemi
catch can will work just fine.. dont need anything fancy imo.. just go look at all the hemi motors, LS motors they all run a catch can system..
My big problem is the valve covers don't have any form of baffling. They were some of the (very early?) cast alum Chevy Performance tall valve covers with raised lettering, my dad got them in the early 2000s if I remember right and never used them. All the photos of the current ones I see from Chevy Performance have built in baffling.

With my rocker & girdle setup I don't have much clearance between the girdle and top of valve cover so the tall grommets with baffles don't even fit. My current attempt is one of the shortest grommets I could find with a bottom that needs "cut" to open it up. Combined with the foam insert out of a baffled grommet I purchased that wouldn't fit. Plus the catch can I just installed yesterday. Will see what it picks up on this next tank of fuel.
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Old Sep 20, 2024 | 06:49 PM
  #47  
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Car: '18 Chev Camaro SS 1LE
Engine: LT1 6.2L
Transmission: T56
Axle/Gears: 3.91
Re: 383 Stroker with FIRSTŪ intake swap

Last summer drag! Air was cooler but not cold enough to get the max mph. Also 60 foot was not best.

60' 1.853

330' 5.251
660' 8.079
MPH 87.07
990' 10.426
1/4 12.527
110.63 mph



Again, with cooler air and best 60foot so far, we get 12.4 @ 112mph. Next spring or fall, I should get there.

Very satisfied with the set-up. The engine is performing as expected around 400HP +/- depending on air temperature. Traction is actually really good for the set-up.
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Old Sep 20, 2024 | 10:54 PM
  #48  
my hemi's Avatar
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From: NJ
Car: A few things lol
Engine: 350 tpi supercharged and a 383 stro
Transmission: Both 700r4s
Axle/Gears: 3.23s and 3.54s
Re: 383 Stroker with FIRSTŪ intake swap

We should be going out hopefully this weekend I'll post up how she did being it's my wifes car and she races it.. best ET to date 12.2 @111 with a 1.6x 60ft that's just leaving it in drive and flashing the convertor.. I really wish i could borrow a set of skinnes actually a whole drag setup lite weight bet she could get this bottom 12s possible high 11s with some practice and shifting higher then stock shift points.
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Old Sep 21, 2024 | 08:22 AM
  #49  
SbFormula's Avatar
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From: Canada
Car: '18 Chev Camaro SS 1LE
Engine: LT1 6.2L
Transmission: T56
Axle/Gears: 3.91
Re: 383 Stroker with FIRSTŪ intake swap

Originally Posted by my hemi
We should be going out hopefully this weekend I'll post up how she did being it's my wifes car and she races it.. best ET to date 12.2 @111 with a 1.6x 60ft that's just leaving it in drive and flashing the convertor.. I really wish i could borrow a set of skinnes actually a whole drag setup lite weight bet she could get this bottom 12s possible high 11s with some practice and shifting higher then stock shift points.
Yes, please post your detail results. I will update post#1 for comparison once I get your results.

60 foot is not an easy task with my set-up (T56). If I get in the 1.7s I am happy. It's all about the right clutch/rpm launch. Not enough, the engine bogs down, too much I get a bit of wheel spin. When I get it right, I can hear/feel torque arm pushing against the subframe and no wheel spin!!!!

Yours is great in the 1.6s.
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