A lot of money for a small gain, so unless he is building to race in a in FAST type class, and needs every last HP, it's really a waste of money. I think people that have done it saw maybe 5hp, it cost over $500 last time I saw someone talk about it and that was maybe a decade ago ?


Listen to fast68plymouth , he has been involved in a number of builds for this.

My experience is the port openings on the manifold are a lot smaller than the ports on the head , especially if the head is opened up to the gasket , port matching the manifold on both the inlet and the outlet to the head pipe , along with smoothing as much as you can reach in can't hurt.

andyF didn't do much of anything to the manifolds he ran, maybe port matched , but he did use a pass side without the flapper valve setup, I'd remove that if the crossover is blocked.