gm 12 bolt conversion.

[Calvindoesntknow]

I was wondering what is involved in making an A body 12 bolt rear end fit in a g body. Is It a better option than a quick performance 9 inch setup?

 

[charlief1]

There are kits designed to fit the A or B body stock rears fit in a G body chassis, but the are issues. Different backspacing of the wheels is just one of them. The 12 GM rear is a good choice but to fit as a "stock" style replacement it has to be narrowed as well as the proper brackets welded in place.

 

[TexasT]

Unless you already have the 12 bolt I would order a fabbed up one.

http://www.moserengineering.com/com.../12-bolt-built-to-order-rear-end-package.html
Just easier and will have new stuff in it.

What are you planning that an 8.5 ten bolt cant handle. To me the next step is a 9 in.

http://www.quickperformance.com/9-Ford-Complete-Rearend-GM-G-Body-78-87_p_20384.html

 

[charlief1]

The 12 bolt will hold up to a lot of abuse and fits better than the 9 bolt, not to mention it's lighter Rich.

 

[TexasT]

Yeah, but if you are needing a 12 bolt, not that much better than an 8.5 ten bolt imo, the somewhat heavier but also more sturdy, nine inch is the same money. Axle retention, gear change are sliding the axles in n out and swapping the chunk, the cool ford parts on your Buick. Haha.
I just can see going to all the trouble of swapping rears and just getting a 12 bolt. Just me.

http://www.v8buick.com/showthread.php?305828-Strength-of-8-5-quot-Grand-National-Rear

 

[charlief1]

The biggest issue with the 9" is the placement of the upper Ears Rich. There are some interference issues with the upper arms, not to mention the extra drag (power loss) that it takes.If I was going sub 9's, then hell yea. But in most cases the 12 bolt is more than enough.

 

[Mr.Spool]

I was wondering what is involved in making an A body 12 bolt rear end fit in a g body. Is It a better option than a quick performance 9 inch setup?

inmo if your going to pull the rear go right to the 9 inch,i did and the 9 inch takes a hell of a beating and the extra weight I in the right spot

 

[Calvindoesntknow]

I'm going to put a 9 inch in. I'm most likely going to find a bronco unit and then weld the tabs on, since I work in a fabrication shop and that would save me a ton of money over buying a prefabricated unit, and then being unhappy with the quality of the welds.

 

[TexasT]

Come on Charlie, everyone with a Turbo Buick is running sub 9s, just ask em. Haha.

I'm not saying a 12 bolt is a bad piece, I just don't think for the time, and money to swap it is worth it. If you are going to beat on the car, and we all know very few launch it softly, the nine inch gives a one time up grade. I would buy the fabbed stuff but I can see where if you can do it, you should.

 

[Calvindoesntknow]

Wait how does one launch softly?
I just picked up a ford 9 inch locally, for 180$ so when I get it appart and fabricate things I will post a show thread!

 

[charlief1]

Come on Charlie, everyone with a Turbo Buick is running sub 9s, just ask em. Haha.

I'm not saying a 12 bolt is a bad piece, I just don't think for the time, and money to swap it is worth it. If you are going to beat on the car, and we all know very few launch it softly, the nine inch gives a one time up grade. I would buy the fabbed stuff but I can see where if you can do it, you should.

Alky V6 (Donnie) is either running a dana 44 or a 12 bolt but don't remember which. He's in the 8's Rich, and his launches were really rough (unbelievably so) until he got the suspension worked out.