You don't have too many choices, but from what I've seen, the Weiand is. Has removable top for access to inside mods and Dominator carbs if you want, and can mount carbs sideways. I don't think the Offy works as well. Of course, if you go with the A460 heads, then Trick Flo makes one, but big $ there.
I know it dosen't look as cool, but in 99% of cases, you'd be better off with an Edelbrock Victor and a single Domminator. Potential for real good pwer there. (700 easy)