ZZ4 with TPI 89 Formula Questions - Third Generation F-Body Message Boards

JP007 · 10-06-2009, 07:05 PM

I just bought a 89 Formula with new ZZ4 motor installed by local GM dealership. Car was an original 305 TPI with automatic. It does have new headers, dual cats and new 3" exhaust all the way back. I will replace the 2.73 rear with a 3.23 shortly. What do I need to do with the TPI and computer to let it unleash all that power. Pretty much a dog when I drove it. Do I need more fuel pump pressure or just 350 TPI injectors? Then some computer work/prom? With the correct updates this thing should run nice and be realiable. Suggestions guys....

JP

vetteoz · 10-06-2009, 08:48 PM

Quote:

Originally Posted by JP007

new ZZ4 motor installed by local GM dealership. Car was an original 305 TPI with automatic. What do I need to do with the TPI and computer to let it unleash all that power. Pretty much a dog when I drove it. Do I need more fuel pump pressure or just 350 TPI injectors? .

JP

Upgrade the injectors if still 305 ones and a custom tune.
The ZZ4 cam responds very well to the usual TPI mods; big tubes , ported / siamised base , etc