Iroc_87

I have a 1987 Iroc-Z with a 305 TPI, if I go with a 350 TPI from an 87 what do I need to change?

And what can I keep? Like transmission, exhaust manifolds, etc.

five7kid

iTrader: (14)

You need to change the engine.

If the 350 is TPI, use the injectors and knock sensor from it. Otherwise, everything other than the long block are identical between the 305 and 350.

The 350 TPI had slightly different PROM tuning, but not so different that the 350 won't run, and run well, with the 305 PROM.

Chrisry1995

iTrader: (1)

Are you getting the motor already pulled from the doner car? This is what I did when I swapped my 89' 305 vinF for a 89' 350 vin8. Changed ECM, because I had it with motor. Don't have to, but it will run better with the prom from a 350. If you don't have the PROM from the 350, as stated by 7kid, it will run. The ECM's are the same, it's the prom chip inside the ECM that's different. The other thing is the knock sensor on the block itself. It's right by the oil dip stick. This is connected to the spark control moduel. That's on the firewall by the relay's. Don't forget to get that. Otherwise when you stomp on the gas, the distributor won't retard timing if you get spark-knock. The car will run, but you risk detonation Big-Time. They are expensive...$100.00 or so. Get it from doner car if possable. The injectors are different as well, but you have them on new motor already. Then, with some 350's, you get the oil cooler as well. This is attached to the oil filter, and runs coolant thought to keep the oil cool. Works fairly well, not great. Just need some hose to attach to existing cooling system....very easy. That's all the differences between the motors. It's just better to make sure everything is changed over. It will run if you don't, but you'll get the most out of the swap if you do. Good-Luck. You WILL notice a difference in power. Do a search, you will find a ton of info. here on the swap.