Ok, so I’ve found a 1991 Firebird with a 305 in it for a really good price locally and I’m pretty sure I’ll be picking it up. But I really want to swap out the engine for something a little more powerful. At first I was thinking an LS1 but it seems like that's a fairly difficult and expensive swap for this body type. Then I started thinking along the lines of an LT1. So I guess what I'm asking is how difficult it would be for the physically fitting and installment of an LT1 into a 3rd gen firebird?

 

the LT1 has the same basic exterior dimensions as the 305 and uses the same motor mounts. There are some challenges to overcome, mostly wiring related. I suggest studying up in the sub-forum at the top of the Engine Swap page called LTx and LSx. I've been reading it for several weeks now to prepare for my own LT1 swap, and there is a wealth of information. redirect has probably every wiring diagram you would ever need and lots of other great info.

 

My LT1 engine swap into my 1991 Firebird was a cold, fun learning experience. This past winter a couple of my friends and I got together over my college winter break (1 months time). I bought a 1994 Camaro for 1000 bucks and got all my parts from the car for my swap (Engine, trans, wire, wire connectors, PCM, ect..) We had the old 305 out in one night. The engine swap took longer due to updates I made to the engine while I had it out. I would highly consider replacing the water pump and distributor. They are a pain to get at after the engine is in the car. Physically, the engine went in with little problem. The wiring process is a different story. I got all my information from the LTx and LSx message board. There is a huge base of knowledge on the Thirdgen web site to answer all your questions.

YouTube - Broadcast Yourself.

Here is a link to the video that my friend created in the process of the LT1 swap.

 

Thanks for the feedback. Now I'm actually starting to check out the LS1 again though. I had heard that the LS1 will fit in the engine bay except that the AC compressor needs to be moved. I was talking to my friend who owns a '99 Camaro with an LS1 and I had heard that he never uses the AC because he has t-tops. So now I’m wondering how hard it would be to install an LS1 instead WITHOUT the AC compressor at all. Again, as far as the fitting and installation goes. clearly the wiring process can be pretty tedious but I don’t think that I’ll have too much difficulty, the painless kits look pretty intuitive and a few of my friends have done engine swaps in their Subaru’s before and know how to do it pretty well.