Yeah, this is what I am trying to avoid. Someone who doesn't know the Stage IV is a completely different casting with wider intake ports and thicker in critical spots for porting. The Stage IV can't even use stock rockers and 5/16 pushrods without major grinding on the outside intake port walls. With 3/8 pushrods, you must use a .450/.500" offset intake rocker (stock offset is .250" offset), so that the pushrod pinch can be eliminated on the inside of the port. The "452" head was available new at the same time as the Stage IV with hardened seats, for 1/4 the price, so yeah-the Stage IV is just a smog head. Thanks for clarifying!
