No need for high heat paint. Automotive grade urethane will hold up fine and be more chemically resistant than rattle can stuff. Urethane may burn off an area of the intake if the heat crossover is not blocked. Not an issue for me as I always block the crossover. I even use bondo to fill small dents in the valve covers. . I put epoxy primer over everything. The stamped steel parts (valve covers, timing cover , oil pan) should be primed for sure.