1954 f 250 change rear end to 70's automatic

[gumman]

Hello, I have a 3/4 ton eight lug flat bed 1954, I want to change the rear end to a ford rear end from a later model ford pick eight lug with drum brakes, hopefully a 411, its 56 inches from drum to drum inside. Does anyone have any information? the engine is screaming at 50 mph, need to cruz at 70 mph, any info would be greatly appreciated, thanks Gumman, Los Angeles

[rwilly]

Not that I have an answer to your question, but I sure would like to see pics of the truck. Can never have too many pics!