Hello,
I was searching on this forum on engine problems. Has anybody on here succesfully switched a third gen TPI 305 engine to a 350 and have it run like a factory equipped 350? Also, has anyone switched from auto to manual on a 350? I wanted to change mine over, but do not want to pour in money and have problems with car. I want it dependable like it came from by General Motors. Thanks! Andrew

 

I did the swap in a 88 Trans Am from a 305 5 speed to a 350 with the same 5 speed. The 350 was a stock truck engine from about 96. Put the TPI system on with a Holly APFR after my stock APFR took a total dump and installed 00 LS1 injectors. Installed SLP headers and y-pipe and a Hooker catback. Bought a new 350 knock sensor and reused everything else.

For the ECU I took a stock 88 350 PROM and copied the Fuel and Spark tables over, adjusted the injector constant to close enough, then adjusted the fuel pressure to get it a little closer. It ran like a champ, pulled really strong and drove like stock.

 

'88 is mass air flow (MAF), and '91 is speed density (MAP or SD). But, still not a big deal, and many, many have done it with SD. In fact, many will tell you it's the way to go if you stay with TPI and up the CID. You can do the 350 PROM, or just get the equipment to burn your own PROM and fix the need yourself.

As for the manual tranny, do you already have something? If you don't, you might want to consider a T56 from an f-body LT1 ('93-'97) - much stronger, double overdrive vs. single of the T5.