Check out the Tremec T56. It's a 6 speed that was put in Camaro's. It will handle the torque and give you two OD's. After a quick google search I see some Wide and Close ratio's available. One with .83 and .60 OD's and the other had .73 and .50 OD's. Both Wide and Close have a low enough first gear to start out hauling a load aswell.

My brother has one in his 66' behind a mildly built up 350. He has hauled a car hauling trailer with it, no problems. Only issue you would have is hooking up the hydraulic throwout bearing. Bolt pattern on the integrated bellhousing is standard Chevy.


58' 3200 235 3-speed/OD