81 Firebird Engine Swap from a Buick V6 to a 350 Chevy
 

Hi All,

I'm looking for guidance on my planned engine swap. I have an '81 firebird, came with a 3.8L Buick V6 and a 200r4 tranny. I'm looking to keep it simple, and swap the 3.8L with a carbureted Chevy 350. I'm looking to keep the 200r4, and intend to rebuild it in time.

I know I'll need a new cooling system, engine mounts, exhaust manifold/dual exhaust system and maybe a BOP adaptor between the Chevy 350 and my 200r4...

I want to know what else I'll need for the swap basically. I'm having a shop do this, as I don't have the equipment for this type of job. I don't want to go in there looking like a fool and get grifted also...

Also I'm concerned about the rear gear ratio and if it'll be able to handle the extra torque. I'm not sure what my car has right now, as finding specs on the 81 V6 models is troublesome for some reason.

I'm looking at this blueprint engine. Its fully dressed with all accessories and such:
https://blueprintengines.com/product...-pulleys-black

If anyone could tell me their experience, recommendations, what additional work will need to be done, if my gear ratio in the rear can hold up, ballpark of costs and anything else I would appreciate it!
:car:

The 200r4 behind the 3.8 will have both the SBC and the BOP bell housing patterns. No adapter is needed. The 3.8 starter is on the same side as a SBC, I think it uses the same starter. The distributer wiring may need to be lengthen too reach the back of the engine, the Buick has the distributer in the front. Been a long time since I did a swap from a 3.8 to a V8, I think the engine mounts on the frame get moved further forward, I think the holes are already drilled in the cross member.

Of course the exhaust and all the engine accessories will all be starting from scratch.

The stock 200R4 behind a 3.8 is not going to hold up very long with much HP in front of it. Really should have someone that knows how to build up a 200R4 for more power go thru it or you will be hiring someone to work on it again pretty quickly.

200R4 has a pretty low first gear and helps with the take off even with highway gears. That is something you can always change later.

It may not have both bellhousing patterns, the early transmissions were BOP only. Easy to check. Doesn't mean it's suitable without work. There's a big torque and hp difference, and you need to know what the trans came out of originally, and your rear axle ratio as to if suitable or not.

Remember to log in again to read any replies you were seeking .I'd be interested to know if that 200-4R is original or not to your 81 V6.

Hi All, thanks for the replies! and yes, the 200-4r is the original transmission with 120K miles on it.

Ok let's see it then. Starting with the console.

thought so

Yes. Have also seen Wiki and a few other copy n paste places make the claims, before GM even released it.