Unless it gets in the way, I think I'll keep the vacuum advance. Gives it a bit smoother idle and really shouldn't hurt performance. Plus my cam grinder curved my distributor and he recommended I keep it... Not 100% sure why though. He's a trusted advisor from 460ford.com so I'm really just doing as he suggests.
I'm bummed to hear about the valve cover clearance. I bought some sweet fabricated aluminum covers but now I'm betting they won't fit because they are much taller and larger than the ones I've got in the pictures.
I'll post some updates when I hit some landmarks. Got the front suspension in so far, not much else. But lovin' every minute!