The 2 door coupe and the 4 door sedan.

Are they mech they same, I know the body's different, but I'm talking about the driveshaft lenght, and rear end mounting points

 

I believe they are both 108" wheel base, so I imagine the driveshafts will be common. At least I recently read a post that suggested that

 

All 78-88 A/G body cars use the same 108" wheel base except the El Camino, which uses a 119" wheelbase. There are some detail differences in the body mounting tabs on the frame, and early cars don't have the same mounting provisions for the crossmember since the 200-4R wasn't offered in the first few years. Driveshaft length varies with trans and rear axle housing (the 8.5" axle uses a slightly different driveshaft length than the 7.5). Other things like motor mounts, radiator core support, brakes, are all pretty much interchangeable. The one exception is the 1978 brakes and spindles, which use different bearings than the other years.

 

OK thanks guys