That's really old, and only for SBC motors. As far as the Weiand tunnel rams, I've got 2 for a low deck- they look different externally, but the mis-match between the top and base is damn near the same, There's an article on HR ...
We looked it over out-of-the-box and decided it needed porting. The runners neck down in height at about the midpoint from the cylinder-head side, then transition to a large cross-section "D" shape at the plenum. We performed considerable porting, carefully measuring the point of minimum cross-sectional area and removing metal in that area. Access to any part of the runners is wide open for porting, with the top plenum removed. Later, we found this note on the Weiand Hi Ram in a Mopar Performance race manual, "For best performance, the Weiand ram should be ported out to the size of the port in the head."
Current link, since HR broke all the old ones The manifold shootout was on a 383, what's not clear is if that is the ported manifold Steve Dulcich used in the older build, or another one he picked up later.
