I agree with Bob S. wait until you see what you have under the car. My 68 came with a 69 Camaro 8.2 C-clip rear not a BOP. I didn't realize it until I noticed the track was one inch narrower on the rear.
I feel your pain.. I have a Chebby Chevelle rear on mine. I don't even know how to figure out what gear is in it.
1957 Thunderbird 289 1967 Firebird Base 461 1968 C-20 327
