Why not just rebuild any C4 that you already have instead of trying to bastardize something else. To do a C4 - really no special tools beyond a dial indicator They are about as simple to do as a 3-4 speed manual. Couple hundred bucks worth of parts from here
or similar supplier, a weekend, and you are on your way. To do a performance build, another few hundred and a heluva lot better then some odd ball transmission for that enging.