I havn't actually installed the small block yet, but I'm very sure that you don't have to relocate the cab.
I had a friend with a 46, he built his own mounts and the cab stayed in place.
The only thing That has to be modified is the firewall. It has to be clearenced for the distributor, if your using the big HEI(which I will, because it's a much better distributor.)
The Motor mount/Trans mount kit from Jim Carter is a great value. It comes with the measurements and a diagram. I highly recommend it. Good luck, and if I run into anything that may help I'll let you know. Mike.
