Hi guys I have a 89 trans am with the 305 tpi. originally i was going to swap the engine with a 350 but the more I think about it the more I want to keep the old tpi. I think the engine is a big part of 3rd gen history but at the same time I want a little extra power too since Im planning on rebuilding it anyway. What are some Ideas to get the car into the low 14s or high 13s with the lb9? high compression pistons, cam?

 

If your car came with the peanut cam (LB9/automatic) cam you will at least want to upgrade to something close to the L98/LB9 G92 option cam.

With a high stall converter, full aftermarket exhaust (from the headers on back to the muffler), and some intake mods (porting the plenum, getting larger baseplate and intake runners, cold air intake, cutting away the baffles in the factory airbox) will all help.

If your car still has 2.73 gears with an open rear end, that will need to be changed to. 3.23 or 3.42 work well with TPI and you won't turn too many rpms on the highway.

 

[QUOTE=yaj15;5640506]If your car came with the peanut cam (LB9/automatic) cam you will at least want to upgrade to something close to the L98/LB9 G92 option cam.

With a high stall converter, full aftermarket exhaust (from the headers on back to the muffler), and some intake mods (porting the plenum, getting larger baseplate and intake runners, cold air intake, cutting away the baffles in the factory airbox) will all help.

If your car still has 2.73 gears with an open rear end, that will need to be changed to. 3.23 or 3.42 work well with TPI and you won't turn too many rpms on the highway.[/QUOI
I thought the 88 and newer tpi's all had the high lift cam, are there any after market companies making cams for the engine, and yeah my car still has the 2.73's lol

 

The '91-'92 LB9's all got the big cam, the difference is power is with the exhaust.

Ha ha yeah getting rid of those 2.73's will make a big difference as well as adding positraction.

Yeah a lot of companies make aftermarket cams that work well with TPI. Check out this link below:
https://www.thirdgen.org/mods3

[QUOTE=lazey8;5640531]

 

I did the 305 to a 350 swap about six years ago. Made the mistake of getting a create motor from a company in Phoenix. Big mistake but learned from it.
I have a custom ground Reed cam that still works with the ECM (upgraded from the stock to a 1992 vet 350 TPI ECM) also have SLP high volume runners and plenum. 58 MM throttle body with an Edelbrock high flow manifold. Complete Comp Cam roller setup and AFR heads. Completely change the wiring harness to a 1992 TPI harness.
I run 34 lbs injectors with the fuel pressure set at 40 PSI.
Rear end is a 12 bolt Moser with 3.73 gears. Quick out of the hole but RPMs are higher when in 5th.
Lots of lessons learned and it still pass CA emissions.

 

Tsires, impressive that you pass CA emissions. Hats off to you. Gives me ideas on how far I can go before I exceed emissions.

 

The Cammy started as a federal car from Virginia but had to get it to meet CA emissions for a federal car. Still has the EGR pump and all of the plumbing. Could have done so much more but wanted to keep it as a road car without a Hassle from the ARB. Headers are Edelbrock and are a tight
squeeze with a complete CAT back system. The Magnaflow exhaust sounds great.