Great thread Tuner. I started the same one on facebook. 1971-1979 van only.
I can find 4.75 cragars all day long, cheap!
I've considered conversion spacers. They do add 1.5" so a deep BS would be fine.
I'm not going to anything until i get to a meet or the nats to get specific info.
No sense in reinventing the wheel (no pun intended).
let stay in touch. the answer is out there.