In 64 I acquired a 36 Ford 5 window coupe with a 301 sbc and stock drive line. In less than a year I blew the tranny and twisted the left axle in half about 3 inches or so from the axle key. The 301 was running a 30/30 Isky cam, reworked heads, early Vette 2-4's and a Scheiffer 10# aluminum flywheel. I put a 39 box with Zephyr gears and the rear end from a 40 pick up in the car and they were still there when I sold the car, minus the engine, in 73.