86 Camaro Iroc 305 to 350 transplant ?

Does anybody know what I should expect in removing a 305 engine and replaceing it with a 350?
Such as electrical, computer, sensors, fit, it is a 5 speed manual if that matters. ?


Thanx, Mike  

The computer calibration is different for a 350. Everything bolts up the same as the 305 as far as external excessories. Unfortunatly the transmission wont tolerate the extra torque. GM never installed the 5 speeds from the factory behind 350's I have seen this done and it will work fine as long as you dont abuse it. If you have upgrades on it and it hooks hard a few times it is gonna break for sure.  

Shouldn't have a problem after computer calibration. sounds like you might need to rebuild and beef up your transmission  

You'll need to get bigger injectors for the TPI unit to be able to feed the 350 enough fuel. That's an easy thign to handle though, just go to the store and get some injectors for a later model 3rd Gen IROC/Z-28 with the 350 TPI system.  

i agree with 55 guy... but you need to know... that you will need to properly reinstall the oxygen sensors... and make them work...

the factory base programming for the 305 is adaptable.. it looks at the air fuel ratio in the exhaust stream...    and recalculates...  without the oxygen sensor feedback.. the system just does not know what to ***

there is one thing for people to know... as many are going to read this post...

any  leaks in the air injection diverter valve into the upstream air injection pipes will dilute the exhaust stream before the oxygen sensor..  the upstream air are the tubes that are screwed into the exhaust manifold right at the head...  the down stream air feeds out of the a different port on the diverter valve and feeds into the side of the exhaust pipe in front of the converter or into the side of the converter..

what happens is the check valves go bad... leaking hot exhaust backwards into the plastic diverter valve.. this eats the seats out of it... causing it to leak..  

exhaust leaks will also fool the oxygen sensor into false readings..

when working properly.. the diverter valve will divert air into the upstream passages to help burn off the fuel and heat the converter...  once the oxygen sensors get up to temp... and the system goes into closed loop... the upstream air is turned off ... the down stream air is cycled on and off... but the down stream air does not affect oxygen sensor readings...

the reason to go to the larger injectors is not just to get more fuel flow...

it is because when  you tromp on the pedal. the fuel injection system goes into open loop... preprogrammed.;... it is set up for an injector pulse width to supply fuel for rpm verses throttle angle verses manifold pressure...  with a 305 injector... this open loop program will be too lean ... leaving you with a flat spot on acceleration..  

This car is a 86 camaro IROC z with a 5 speed trans, 305 engine with a Quadrajet carb. Not fuel injected.
Thanx guys !

You guys have already helped me on some important decisions.  

Well darn,  waynep712 all that typing went to waste but I must complement that is a very good explanation. I take you have had this trouble before.