Headers

One gotcha on buying pre-coated headers is you might end up needing to ding them here and there. And by ding I mean you might need to beat the living crap out of them to get them to fit. I needed to make power steering and torsion bar clearance on the Doug's that going are in my 71. If you're worried about ambient underhood heat, imagine how little good it does anything to actually be in contact with a header tube.

Consider having them coated after you know they fit.