About 4 steering options.(depending on goals)
1. Radical: Mustang II thing, aftermarket rack and pinion.
2. Less radical: $300 power steering kit which mounts modern box on outside of rails. Then good flow Tube headers.
3. Lesser/easier: Move stock box outward on home made bracket. (enough said)
4. Easy: use 55-56 265 V8 left hand cast iron low flow exhaust manifold (or equiv.) to clear stock box.
DON'T QUOTE ME on any above, they are possibles, I have not done them.
I would do no 2. (source: CPP)
Carl, Using stock frame and using tranny made for the motor are excellent moves.