Insulating Against Heat on the Carb

I am running the OEM style thick paper unit under a 625 Carter on my 68 post. No boiling issues. I do have a hood scoop though so I'm sure that helps reduce under hood temp. The passenger exhaust manifold is non EFE (early fuel evaporation) valve type also. The crossover is open on both intake gaskets. Big blocks are easy to cheat on since they have no water passage. You can cut a piece of tin can lid loosen the intake and slide it between the manifold and head to block the passage. I would be afraid you might get a water leak trying that on a small block.