Hey guys first time poster.

So im building an l67 ISH motor. The bottom end is from a 2000 firebird. Flat top pistons which are 9.4:1 vs the 8.5s the dome stock l67s have. 2.8 pulley, intercooler. Heads are ported, larger stainless valves and milled .030. Zzperformance NIC camshaft with headers. Im porting the blower and using a Northstar throttle body that will be ported. Manual 5 speed izuzu trans
Here's the questions I have:

1: pushrod length. Just wonder if anyone knows off-hand with 1.65 rockers, .030 milled heads and .063 head gaskets what size is best? I assume shaving .030 and then adding .050 on the rockers id be .020 shorter which is within tolerances. But maybe im wrong here?

2: on the subject of head gaskets... this engine was bored .040 over. Does anyone know or have a link to a company that has .050 or .060 bore multilayer head gaskets and or can I use L32 gaskets from like an 08? [Im actually a gm world class master technician, so ill just get them through my parts department if I could]

3: on a stock 99-03 pcm. Can they run a flex fuel sensor? I asked my tuner and he said hes never dealt with the blue and clear style pcms.

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Matt Pelissier

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Matt Pelissier

For question 1 and 2, I built my 3800 on a standard un machined block with a stock valve train. So I won't be much help there.
For question 3, I suggest you reach out to Ryan of GMtuners (Darth Fiero). He's the PCM guru for all things 3800. (I have a doubt that the 2000's PCM could handle flex fuel?)
Though why bother with ethanol? You'll get easy 350/400HP with pump grade petrol (gasoline).
As well, I'm not sure that your 5-speed Isuzu will hold up to the torque for very long?
But whatever, that's a nice build you have started there👍😉

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"Turbo Slug" - '87 Fiero GT. 3800 turbo. - The fastest Fiero in France! @turboslugfiero
https://youtu.be/hUzOAeyWLfM

Ryan at Sinister Performance (gmtuners com) is the go-to guy for tuning and PCM questions.

Im am very afraid of the trans. If i didnt already spend a bunch on the flywheel, clutch, mount kit and new axles, i would have purchased the f40 off of zzperformance. As for e85... im running a 2.8 pulley. I want as much room as possible on timing. The intercooler gets me pretty good but e85 makes it much better. Im shooting for 500 hp

quote Originally posted by Frenchrafe: For question 1 and 2, I built my 3800 on a standard un machined block with a stock valve train. So I won't be much help there. For question 3, I suggest you reach out to Ryan of GMtuners (Darth Fiero). He's the PCM guru for all things 3800. (I have a doubt that the 2000's PCM could handle flex fuel?) Though why bother with ethanol? You'll get easy 350/400HP with pump grade petrol (gasoline). As well, I'm not sure that your 5-speed Isuzu will hold up to the torque for very long? But whatever, that's a nice build you have started there👍😉

500 is nice.
I could easily go 450 (got 447 on the dyno one day), but like I said before in this forum, the gearbox wouldn't take it in a real world use on track etc...
Talking about real world things, what have you done for suspension, tyres and brakes?
Going fast is one thing. Stopping safely is much more important.
Going fast round corners and having good controlled braking and handling to attack the corners beats pure power output every time.

P.S: How much is an F40 trans costing these days?

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"Turbo Slug" - '87 Fiero GT. 3800 turbo. - The fastest Fiero in France! @turboslugfiero
https://youtu.be/hUzOAeyWLfM

[This message has been edited by Frenchrafe (edited 12-02-2025).]

I would be scared for the transmission as well. It will not survive the torque you will be making with that setup.

My best advice to you after doing swaps for the last 15 years is to save yourself the time and money later and put an F40 in it now.

Do it once and do it right, or break it later and suffer the consequences.

quote Originally posted by Mattrevenir: Im am very afraid of the trans. If i didnt already spend a bunch on the flywheel, clutch, mount kit and new axles, i would have purchased the f40 off of zzperformance.

https://thedecisionlab.com/...he-sunk-cost-fallacy

Thanks for the tip

quote Originally posted by olejoedad: Ryan at Sinister Performance (gmtuners com) is the go-to guy for tuning and PCM questions.

The first time on track with stock '87 brakes and a 400HP engine pushing hard, I completely cooked the brakes!
The front discs overheated and cracked! The rear brakes just stopped working (maybe fluid boiling?)
You will need to upgrade a bit, even if it's just for drag racing. Nobody likes that "brown trousers" moment when the car won't slow down on the escape lane!

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"Turbo Slug" - '87 Fiero GT. 3800 turbo. - The fastest Fiero in France! @turboslugfiero
https://youtu.be/hUzOAeyWLfM

quote Originally posted by Mattrevenir: 1200 bucks for the f40 on zzp. Its temping AF. Not much on braking yet. Do have coil overs for the rears. The front i have no plans as of yet. I need to get it running and mobil first.

Be sure the ZZP F40 has the correct bellhousing pattern for the 3800, or an adapter plate.
Also don't forget about axles and intermediate shaft and intermediate shaft support bracket and bearing.

The Isuzu axles will not work with the F40.