Intake sealing and blocking the heat crossover

No heat crossover needed in Yuma, AZ. Argue away.

When I blocked mine, I took it up a notch, literally. On my 318 A, I milled a step in the intake manifold crossover port the circumference of the crossover. I then milled a 3/8" steel plug with a corresponding step in the outer edge. Secured it in the manifold with high temp silicone. It sits barely above flush and is held tightly with the fiber gasket. No burn through here.