Great advice from all above...I was thinking ram horns but coilover has done it already with his idea. I would mock motor in middle, set pinion correctly then observe what steering and manifold will work. Mock-up is THE only way to proceed. That's how you do it "once". If you don't want to stay stock, the outside frame Saginaw mentioned is best for your application and kits are available. Box and pump easy to find/replace.
http://www.classicperform.com/tech_articles/Power-Steering-Trucks/Power-Steering-Trucks.htm OR
http://www.classicparts.com/1947-59-Power-Steering-Conversion-Kit/productinfo/76-977/#.Vcf2VenbI5shttp://www.classicparts.com/1947-59-Power-Steering-Conversion-Arm-4/productinfo/76-986/#.Vcf2hOnbI5sPinion angle, if you mean your diff pinion is pointed up at rest, you are correct, that is not optimum. The idea is to point down (negative) 1-3 deg so when diff "winds up" on acceleration, angle becomes toward zero. Tailshaft to drive shaft angle should be equal and opposite. (The 1-3 is for leaf springs and your HP according to Currie and others). Those values will work for almost everybody on Stovebolt. The average U-Joint is designed for 1-3. Setting up at 2 deg is said to be a great target. Be sure your carb mounting surface is level at loaded rest. Moving motor mounts and tranny mounts back to center should not be too bad. Good luck, really good you are doing it right.
Shifter, cables, throttle linkage, tranny lines, fuel lines, radiator hoses, exhaust pipes may need reviewed/repositioned. Rear shocks/mounts may need reviewed/rotated. Make sure slip joint is proper during mock-up.
