Well I got lucky and scored the correct perches locally on Craigslist. So I figured I'd post some pics of them in the 62 truck with a 72 cross member and engine perches from a 65.
I bolted them to the motor mounts and then dropped the engine down onto the cross member and holes lined up perfectly. The bolt dropped right in.
At the top there is a 1/4 inch gap that will need to be shimmed. I'll use some of the old 72 frame pieces that came with the cross member to make those.
Front shot.