My brother has a 66' with a 350 bored .60 over with 3.73 gears.
He installed a Tremec 6 speed out of a Camaro in it and it has held up to burnouts and towing a carhauler with my 1958 3200 on the back. It has been a solid trans for him. Stock Chevy bellhousing pattern, as the tranny has the housing integrated. He did have to rig up the hydraulic clutch though, wasn't too difficult.
