I did the ZF swap in my '78 F250 with a 400. The 400 crank is around 1/2" shorter than the 460, I put a couple of washers behind the pilot bushing so the input shaft would have enough contact with the bushing. I used the flywheel and pressure plate from the 400 and a clutch disc from the 460 truck. The tranny I had was a hydraulic throw out bearing style, if you can, find a ZF that was a mechanical clutch. I welded the pushrod part of my clutch fork to the inner part of the ZF fork. The tranny mounts are the same, I had to move my cross member back about 1". My rear dirveshaft worked fine, but it was a little short after my lift so the tranny swap fixed that. I didn't have a front shaft in at the time of the swap, so I don't know about the length on that one. You also have to pound the body seam behind the bellhousing flat with the firewall.