sammartin1980

hey guys i need some input on this because i really dont know. ok i have an 85 trans am with a 305 tpi.im wanting to get rid of the 305 and go with a 350 tpi.i know when i do the swap i will have to change my injectors and put the 350 injectors in it.what im wanting to know is,will i have to change the computer and any of the wiring harness?also should i keep the electric fuel pump or switch out to the manual fuel pump on the motor?i was going to just put a different cam and a set of vortech heads on the 305 but after reading alot about it ive decided it would be cheaper and to my best interest to put the 350 in.thanks for your help guys.

87WS6

iTrader: (1)

You will need to reprogram the PROM and get a knock sensor for a 350. The 1985 cars have a lower pressure fuel pump so that may need to be upgraded as well.

sammartin1980

ok if i cant get the comp reprogrammed.because i mean there is really no place around here that does that.out of what vehicle would the comp work on my car?i have plenty of junk yards to get one.or i can go buy a new one i guess.

87WS6

iTrader: (1)

I wouldn't let PROM tuning scare you too much. You just need the stuff to actually do it. In any case even if you don't want to do that you can get the PROM you want from a 1985 Corvette. They used the L98 engine (350CID) and the same TPI setup. The 1985 TPI system used in both the Corvette and the Camaro Z28/Trans Am is unique for that year. So you will have to get the PROM from a 1985 Corvette specifically, and nothing else. The wiring harness, ECM and PROM is different on 1986 and newer TPI systems. Though the plenum, runners throttle body and intake manifolds (intake manifolds were changed in 1987 and up vehicles) are pretty much the same as with other newer cars.

sammartin1980

ok that will work.i been wanting to get rid of this 305 for awhile but just didnt know about doing it because i want to keep the tpi i didnt want a carb.