I put a Tremec 5-speed behind my '67 I6 with the mid-position shifter and a auto trans crossmember. I eliminated the crossmember under the bellhousing completely to gain exhaust clearance. Used all new I6 clutch parts and the stock bell with a retro Ansen Aluminum flywheel. I didn't have to make up any other spacers or special parts. It was a total bolt-in.
Worth every penny!