A picture should not be necessary. Just look at the center of the intake face any small block cylinder head and they are readily apparent. The heat hole was designed, I believe, to transfer heat to the intake manifold. That hole I understand, but aftermarket intake manifolds have no provision for the heat transfer, so it of no use for our purposes. The "slot" that surrounds it on the top, left and right is the one that seems to confuse me. Have i made it worse?
