]You can but you have to change the spring perches the first gen is different than the second generation the first gen are angled and a different withe

 

I've read that the 8.5" rear from the '71-'74 X-body, like Nova, Ventura, Apollo, and Omega, is a direct bolt in for a 1st gen Bird. Check it out and see what you can find ! That will keep you from having to move the spring perches, if they fit.

 

If moving the perches is the only factor then I feel comfortable with the swap I have read 2nd gen rears are slightly long but not enough to worry about thanks for your help guys any other suggestions you can think of please tell me thanks!

 

This info is all correct. I have an 8.5 from a 2nd gen in my car and they only had to move the spring perches. I also had to shorten the drive shaft about an inch, which is what you will also have to do since you also have a TH400. The snout on the 8.5 is longer then the 8.2 which comes out to be about an inch.

 

It's a piece of cake.

Many years ago I had an 8.5 rear from a 77 T/A in my 68 Bird. The 8.5 is MUCH stronger than the 8.2 and as long as you swap out the spring perches and shorten the driveshaft, it's a direct bolt in. I did mine in a weekend.

When I did the 8.5 swap, I had a pretty healthy 455 in my car and that 8.5 took some serious abuse from my 455 and never broke. Unless you are doing a correct numbers matching ride, I would NEVER spend the extra cash for a correct Pontiac 8.2 when the 8.5 can be had for a LOT less money.

 

http://www.carcraft.com/techarticles/ccrp_0603_budget_10_bolt/

http://firstgenfirebird.org/forums/ubbthreads.php?ubb=showflat&Number=280248&page=3

http://www.camaros.net/forums/archive/index.php/t-202937.html

http://www.afbforums.com/index.php?/topic/34622-12-bolt-rear-end/

http://nonnova1974.tripod.com/oldsomegadotcom/id3.html

http://www.stevesnovasite.com/forums/archive/index.php/t-115321.html

The big 10 bolts ( 8.5" ) that came in 71 and later X-bodies are a direct bolt in for 1st gen Birds. Drive shaft will have to be a tad shorter.

 

thankyou for the links they were extremely helpful i think im going to go with the 2nd gen rear alot cheaper and its built how i want it already for $875.