I am buying a 90 firebird with a V6, but it does not run. I am going to take the 305 out of my 85 TA (twisted front end). The motor has about 108,XXX miles. Will the rear end that is behind the 6 hold up?? Thanks for your input.

 

THere is no difference between a 6-cyl and a V8 rear end if they are both 10-bolts.

 

Thats what i thought. neither have posi. thanks

 

V6's come with a 3:42 gear compared to the V8's 3.23.

 

Some do; some don't. My V8 car came with a 3.73. Some V8 cars come with a 2.73. It varies with the specific engine and year combination, and is subject to special ordering.

Gear ratios vary widely, even from one 6-cyl setup to another, or one V8 to another. Posi is the same way; some get it, some don't (very few 6-cyls do, obviously).

But the rear end model is the same. Same housing, same axles, etc. etc.; same strength and durability in other words. There's no reason you can't use one's rear with the other's motor. In fact, since the 6-cyl cars often have better ratios, sometimes it's cheaper to go to the boneyard and snag a 6-cyl rear to get good gears, than it is to change the gears in a V8 car's rear; especially if the V8 car has drum brakes, and upgrading to discs is not an issue. Which is another option feature that is very rare in 6-cyl cars.