I put a small block in my panel using the motor mount kit that does not utilize a crossmember. Using the measurements that came with the mounts it bolts in beautifull and I was able to have room for the automatic column shift linkage to get between the valve cover and firewall.
I am also using the big distributor and I can still get my finger in behind it so I know I can get the dizzy out if I ever have to. Another point it that rather than cut the firewall I would have gone to the small distributor and and external coil to avoid cutting the firewall.
Oh, and yes, I used a power steering box outside the frame. When doing this just be sure to measure your double "D" shaft or what ever steering shaft you use.... measure twice, cut once.
Hope this adds to what the others have said and helps you out.
