Originally Posted by Cam Cook
I have a 1981 Cadillac Eldorado. I would like to know if any of the other big block caddy engines will match up to the THM325 tranny and what other problems I might have.
The TH325 uses the same BOP bellhousing as all other non-Chevy GM motors from the 1960s-1980s. Unfortunately, you have two problems. First, the TH325 is based on the TH200 and will not survive under any kind of torque. Second, your Eldo could have either an Olds 307 motor or a Caddy 368. The Caddy and Olds motor mounts are completely different. If you do have a Caddy motor currently, then other Cad motors should bolt in. If you have an Olds motor currently, then other Olds motors should bolt in.