Originally Posted by cobalt327
Bolt size for bellhousing to block is 3/8-16, length as required for the bell you have.
Same thread for the pressure plate, but a 1" under head length, and not threaded all the way to the head. Use hardened flat washers and a dab of loctite. You could use a set of ARP or similar bolts for the flywheel to crank and pressure plate to flywheel if you don't have the original hardware in good shape.
Am I using flat washers everywhere?