I have a 1969 Firebird and it has a Chevy rear end in the car currently, I found a 1979 trans am posi near me and was considering swapping it in. Has anyone done this before and any suggestions good or bad. The current unit works but would love a posi unit
The springs are further apart on the 2nd gen Birds. So, the spring perches must be moved closer together, for it to bolt into your 1st gen Bird.
The Lots of the X-body cars, from the early to mid '70's, such as Nova, Omega, Apollo, & Ventura 2, had 8.5 rear ends that will have the perches in the correct location. This swap will probably require a different length driveshaft. The guts of these are the same as the 8.5's that came in '71-'81 F-bodies. But, as mentioned, the spring perches are in a different location.
Make sure the chevy rearend you have now is not a 12 Bolt, or an 8.5" 10 bolt, If it is just put a posi unit in it, Here is a web site with info about the rearends http://www.novaresource.org/axle.htm
The 8.5" 10 bolt didn't come out until 72 , so if your looking to change the rear end look for one from the different cars that oldskool posted but 72 and up. They will bolt right in, but the drive shaft will have to be shortened one inch. I have an 8.5" from a 72 Nova in my 69. The 8.5" was GM's replacement for the 12 Bolt and is almost as strong, and still fairly pretty cheap. If you get lucky and find a 12 bolt in a 68-71 X-Body it will bolt right in with no mods to the driveshaft. Also the 2nd gen F-Body's rearends are a little wider than the first gens.
Somebody on this site in the past couple of years swapped in a late 2nd Gen T/A Disc Brake rear and discussed the issues. Do a search.
1967 FB 400, original CA car (smog), now 455, soon to be out of Paint Jail 2006 Mustang V6 Pony, factory ordered, retirement cruiser and future classic(?) Old projects, gone but not forgotten: 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302 1994 Chevy K2500 HD 4x4, 454 TBI
Not trying to start an argument. But it is commonly known that lots of vehicles came with an 8.5 rear end in 1971. I've read that most all '71-'81 F-body cars had an 8.5. Can easily be confirmed with an online search.
I'm not sure what rear end a 1971 Ventura had. But, I'm pretty sure that all the '72-'74 Venturas had the 8.5. Not positive.
The Appolo & Omega first appeared in 1973. I've read that some of the X-body cars still had the 8.5 rear end, after '74, IF they had a V-8 engine. Can't confirm.
I've had my 8.875, 3:31 posi, since 1981. Even back then, forget expensive, they were impossible to find. If you could find one, they were about $1.2k to $1.5k, incredibally stupid money back then. I got it tossed on a horse trade for a '64 Chevelle SS vert I owned. And the rear was the real motivating factor for me to ditch the vert, even if it were a Chevy!
[quote=oldskool]"...The 8.5" 10 bolt didn't come out until 72..." Not trying to start an argument. But it is commonly known that lots of vehicles came with an 8.5 rear end in 1971. I've read that most all '71-'81 F-body cars had an 8.5. Can easily be confirmed with an online search.
I am not either, . I was referring to the X- Body cars as they are the ones that will bolt into the 1st gen F-Bodys with no mods, other than the driveshaft. But I was not aware of the 71 F-Bodys having the 8.5"