My plan is to swap out the stock 305 "HO" from my 91 Formula and replace it with a slightly used GM crate 350. The 350 is TBI same as the 305 and I'm hoping that since the actual throttle body is bigger on the 350 I should be able to just plug my 305 computer into the 350 throttle body and she will run.
Does anyone know if this is going to work or do I need to find a 350 computer for a TBI setup? I checked the part numbers and both the 305 and the 350 run the same O2 sensor so I'm worried she might read rich all the time which will cause me more problems than just a check engine light.
Any advice would be great. Thanks.

 

You might get it to run, but it will not run well.

Since this mostly involves TBI-specifics, I'll move this to that forum for you.

 

Agreed. Swapping the motor without changing the appropriate software will not yield a car that is fun to drive. Speaking from experience here.

You might be able to swap just the prom and keep the stock ECM, but I cant remember off the top of my head if the 350's used the 8746 ECM that your car would have. If you really want to get into it then I'd recommend getting all the equipment needed for burning your own proms.

 

My car is running a 350 and all that was done is plugging in a new prom from a Corvette Seems to run well. Heads were opened up a bit, stock exhaust, and stock throttle bodies.

 

Oops, sorry, I'm still running the crossfire setup on mine.

 

Haha, but it does help nonetheless.

You can get a prom from TBIchips or PCMforless. They make proms that work for a 350 TBI swap. That's if you don't want to burn your own, or don't know how to.

 

When I first did the swap in my '89 i ran the stock tbi on top of the 350 for about 6 months while i gathered all the tpi parts. I used a tbi chip from a Chevy Impala police car with the 350, it seemed to work ok.

 

I think you can get a used 350 truck tbi ECM with chip rather cheap. 1227747 should work. I just saw one on ebay for $49. You will also need a 350 knock sensor from what I understand.