I had always figured 2 x 500 + 350.

although, that is a pretty healthy figure for the end carbs.

I have one of those aluminum high rise 6 bbl intakes for small block, along with a set of reproduction Holley carbs for it. was a christmas present probably 15 years ago, maybe longer. never used it on anything yet!

in fact, here is my intake



I love that manifold. Would love to EFI it with 3 throttle bodies