Converted over to slip on and had to get the donor ds shortened to 59.5" center of yoke to center of yoke. Original tranny was th350 behind a 305v8, no way it stand up behind my bbc for long if I played with it. Which I AM. Lol. Hey best of luck to with ur build. Hope u have fun. Im hope to stroke mine out in the future to a 496 and have some reL fun. Th400 was several inches long err r which is why the tranny mount had to be moved towards reRend. But again the frame bolts were pre-drilled from factory in anticipation of possible engine/tranny swap. #sohappyitwas.