If it were mine, I'ld do the tried and true small block. They're cheap and plentiful and can be built for almost any purpose. Also, I think your truck could have had one, so proper parts to install should be available. If you lived closer, I would trade a 350 for your 427 (sounds fair doesn't it?). Anyway, That's my $.02.
Scott

Scott Ward

2 1948 1.5-ton Loadmasters
The red one and The snow pusher
1 1950 3100
1 1955.1 Chevy 6500
1 1954 Chevy 6500 2-Ton
1 1955 1st Series COE 5700
1 1963 K20 (454)
1 1964 C10 (350)
1 1951 1.5-ton Dump Truck
1953 and a 1956 Ford F800

Raising a teenager is like trying to nail Jello to a tree!