The Stovebolt Site Forums The Shop Area Engine Shop William's, a Fenton knockoff and a poor product.

Yep, that looks like the only way to get them to fit, make your
own. Obviously the after market intake is different than the
stock single manifold. The stock center clamps won't work
without heavy grinding and in some cases they aren't long enough
to span the two flanges, only grabbing them by a 1/16" or so.

DG