Hey guys, I recently picked up my first third gen, and man am I excited to get it on the road! I got a killer deal... 89 RS, siezed engine, very good body, clean interior, 400 bucks! :lala:
Anyway, I have an 87 350 that I'm putting in as soon as it warms up a bit, but I have a few questions. I'm reusing the heads, but if the 350 has different compression pistons than the 305 will it mess with the computer at all? Also, do I need to replace the computer and/or injectors? Any help and advice about this swap would be very greatly appreciated! Need to get on the road ASAP! Thanks

 

go to tbi board search then ask either NJSpeeder or Jprevost.
both have swapped

 

I did that swap. I used a bigger cam than stock with everything 350. I am using the stock injectors and computer. THe computer is capable of adjusting. Mine runs very hard.

 

if your going to do the swap, youll probably want to get the 55 or 65 pph injectors. Youll definatly want to get winaldl or some other data logging system to keep an eye on it. The car can seem like its running fine but the computer could be letting the engine go real lean and before you know it, the engine is toast.

 

The computer is capable of adjusting, but not that much. New injectors are a must. And proper prom tuning is highly suggested. You might make more power with an un-tuned 350, but your not getting the most out of it with out a custom chip. Dont forget the knock sensor too. That needs to be changed out for a 350 knock sensor. Also why are you reusing the heads? You going to choke your motor by putting those crappy 305 heads on the 350. Those heads are horrible on a 305 how do you think they would be on a 350?

 

I did this swap myself, and I agree with everything that's been posted so far. You definately need the bigger injectors from a 350 TBI (I just swapped the entire units), knock sensor, and custom chip. And why keep the low flowing 305 heads on an engine with 15% more displacement.