It's probably one of the original 1960s Log Manifold. What we used to refer to as a 6-pack manifold. Without seeing it, I would say it was meant for 6 Carter or Holly 1 bbl carbs, with progressive linkage. They look great on an engine in a hot rod, but looks are deceiving. They're hell to tune, and performance wise they fell far short of a standard 4 bbl carb.