So I've got a new 83 Firebird, a 80's Chevy 350 crate engine, and a couple automatic transmissions. What will I have to do specifically to put this in? Like, the motor mounts should be the same correct? What about electrical like ecu and whatnot.

 

Welcome aboard thirdgen.org.

A lot depends upon what engine you have now. If it's the base 305 V8 with quadrajet carb, it's mostly a matter of taking out the 305 and bolting the 350 in its place, with all of the stuff that was on the 305 put on the 350 (intake, carb, distributor, sensors, etc.).

If it is a Crossfire 305, that gets a bit more complicated.

If it's a V6, then you need to read the V6 to V8 swap sticky in the top section of this forum.

 

Well it had a built 350 put in it when I got it, but was pulled before it got to me. So by hooking up everything normally, throttle ecu wouldn't limit the motor's power electrically?

 

The factory computer controlled quadrajet can easily handle any streetable 350 out there. Some did have a travel limit on the secondary air valve opening, but there's a good tech article linked from the thirdgen.org homepage that describes what to do about that. Personally, I've never seen a carb with that limiting feature, but I'm not doubting they exist.

Hopefully you have all of the factory carb, distributor, harness, sensors, etc.