Thanks, guys.
Jacksoni- no, I'm not doing a SD. I'll use half of my "junk" aluminum 389 block. I'm probably remembering wrong about Tony saying his crank is billet.
Richard- is vibration difficult to contend with? Solid mounts?
I'll plan on talking with King's about a billet. There's a good chance that it was Jack King who expertly added center counterweights to the 389 SD forging that's still going strong in my hemi V8, after eleven seasons of pulling competition (about 900 HP, to 9,000 RPM).