I have recentley aquired an 86 iroc-z with a 305 and planed on puting in a 350 but have herd that the computer would need changed to a 350 computer or it wouldnt idle right is this true?
any ino would be helpful on this matter thanx!

 

you just need to chip it... or re program it.... OR! you can just toss a carb on it and not worry about the computer.. thats wat i did

 

would like to keep the Tpi, so were would one get a chip ?

 

that i don't know.. search around on the forums you'll definitely get your answer. sorry can't be more help

 

daghstdrummer so how is that carb setup working for you. What did you have before it TBI. What motor did you put in your car

 

I did have a tbi before, i took the harness out and computer and only left the wires for needed for the starter and distributor.. i ran all new gauges and wiring for the gauges as well as fan wiring (since it was all computer controlled to begin with) the carb setup works great i dropped in a 010 block bored .30 over with a summit bang for buck kit and rebuilt stock heads with 1.6 roller rockers... the motor has power and its fun to drive.. i am still tweaking it little by little.

 

The '86 TPI system is MAF, which isn't that sensitive the displacement changes. The '87-'88 350 TPI did have a different PROM ('89 eliminated the cold start injector), which helped get a little more power out of it vs. the 305 tuning, but it isn't necessary just to get it to run, or run well. But, you could replace the PROM with an '87-'88 L98 chip, and that would take care of it.

You should change the injectors from the 19 lb 305 pieces to 22 lb 350 injectors. Whether you need to change the knock sensor isn't as clear.

'86 also was the last year for the intake mount bolts all at 90 degrees (except Vette L98's maintained that bolt pattern). If your 350 has '87-later heads, the TPI base won't fit without modifying those bolt holes.