Those set ups look pretty cool, I've had a couple and sold them, kinda neat on a roadster. I think the Carter YH is like 190 cfm but if you look at how the are mounted back to back I don't think this could be a very efficient flowing manifold, good for low profile though.
God Bless.
Tim http://yblockguy.com/
350ci Y-Block FED "Elwood", 301ci Y-Block Unibody LSR "Jake", 312ci Y-Block '58 F-100, 338ci Y-Block powered Model A Tudor
tim@yblockguy.com Visalia, California Just west of the Sequoias