This guy at my college is trying to tell me that some 3rds cam with a 12 bolt from the factory, i dont believe him, is this true?

did they ever use a 12 bolt? i would guess mabie the TTA but other than that...

 

Nope...Never....WHY???

The third gen in stock form was a turd. Why would it need it. The TTA used the same 10 bolt as everthing else. GM NEVER put a 12 bolt in ANYTHING production after the early to mid 70s.

This of course don't include one off freaks and vehicles built to abuse drive train compunents.

 

From 1985 through 1989 some 3rd gens came with the stronger nine bolt rear end made by Borg Warner. Otherwise they came with the 10 bolt.

I don't know this but maybe some first gens with the 396 motor came with 12 bolts.

 

I was under the impression that the 9 bolt was even weaker than the 10 bolt.

The 12bolt was an option with the SS package with the SB or BB. I beleive it was standard with the BB M4 cars.

 

the Borg warner units were made from 1987-1990 and they were posi..although there were some posi 10 bolts as well

 

That would be a G80, or G92 package.

 

They were available 1985 through early 1990 model years.

Not all were posi. I have personally seen a 3.08 non-posi 9-bolt with drum brakes under a 1985 T/A.

Also, the 9-bolt is/was stronger than the 10-bolt. Not a bunch, but enough for GM to consider it the upgrade rearend.

The TTA used the 9-bolt.

For more info, check www.thirdgen.org

jms

 

Right, the nine bolt is stronger than the 10 bolt. Some say close to the Dana 44 axle. You can buy the TA rear cover to make it even stronger. The cost was the reason the nine bolt was dropped.

 

I have over 500 passes launching nitto drags and bf drags on my 9bolt. It is a beast!! 5,000 rpm dumps with heated bf drags and nothing has ever broken.

It is a real strong unit from my experience.

 

parts are easy to find, axles have to be custom made, 3.27, 3.45 and 3.70 are the common gears,
I got 1 of each