Traditional trans will bolt to LS with the exception of one bolt and you also have to get a special spacer for the pilot bearing. See the book the previous poster refered to, it has good info.

You will have to convert to side mounts, as far as I know. There is no reason to regret that as there are LS conversion mounts to go to normal small block Chevy mounts. I would assume if there are front mount holes in the engine to go with the stock mounts the fabrication would be just as if not more problematic as the side mounts.

I don't know what trouble there is with the AC compressor and stock manifolds. I have the motor and trans and the truck frame but have not started to put the two together.

I do think the LS is a good choice given the cost of small block crate motors and what an LS will put out with out complaining.

R-Bo

1959 Apache 1/2 ton Big Window, Short bed Fleetside (under reconstruction)
1966 GMC 305V6 in the family