O put one im my 68 Ranchero 500 390 4 speed because I wanted to keep the 350 gears but drop the rev's a bit on the hyway. It worked out great and when the Tremec's came out I bought one of those as I really liked the overdrive. I cut the side of the tailshaft and brazed on an adaptor to fit the stock toploader hurst shifter on and in low I could really lite the tires up. Put 10,000.00 miles on that free trans before I sold it to a friend with a 66 Cyclone and he still beats on it. A friend up the road from me ran one in his 66 396 El Cameno and he also had no trouble until he wore it out and he drove peddle to the metal. Good luck, have fun. By the way, the new Tremec TKO 11 that I bought was a nice step up except when I tried to back it off my hoist, it fell out of reverse with a big bang because somebody in the factory forgot to machine the reverse slider and it was 3/16 "to long. I will always trust a toploader and I have worn out lots of them.
