My dilemma, I am going to need to block the heat passage from the heads to the intake. I have 906 heads and an RPM intake (on a 400ci), whats the best way to block the riser, should I cut a thin piece of metal and sandwich it in the bathtub gasket, or should I fill the head or intake passage with something? I am leaning toward filling the intake, but I'm not sure what to use that would stand up to the heat.