I know i'm gonna get flamed, but isn't a 3.8 like a 305 w/o 2 cyl anyway? I know the 231 has the same bolt patterns as a 305, so the trans should just bolt up. What do I need to make the swap? Would a 98+ 231 work in a 90 Firebird?

 

Just here to flame you...what the hell are you thinking!?!?!?!?!

 

Are you speaking of the Buick 231? If so, the belhousing is different. The tranny will not bolt up. I have that engine in my '81 Elcamino, and I want to swap a 350 in, and I needed to get another tranny for that reason.

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'82 Firebird, dead stock, 9 bolt disc rear, over 200,000 miles and still going strong, more to come...
http://www.spinfrenzy.com/stingerssx...easures.html#4

 

So I was wrong!!! Then I need a V6 tranny! Maybe I should re-think this

 

This is one of those "yes, it's possible" deals. There are, however, a lot of "buts".

Yes, the 231 has more power than the typical 305, but getting all that it takes to make it work in your Firebird would be a nightmare.

Either work over your 305, or go for a 350.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R. 2.93 limited slip. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 w/LB9 block, ZZ3 cam and intake, WP 305 heads ported & polished, Hooker headers & y-pipe, hi-flow cat).
57 Bel Air, my 1st car. 0.030 over 396, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" headers, TH400 w/TCI Sat Night Special conv & shift kit, 3.08 10-bolt, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere. Daily driver while Camaro was being put together.

 

4.3 will bolt up it has the same bolt pattern as a SBC

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ICON Motorsports

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