Thermostat housing bolt

I used stainless since I have seen enough rusted T-stat and w.p. bolts. Only exception was the real long bolts on my small block which I had to buy Grade 8 chromate coated. I coat the threads w/ Permatex gasket sealant if they penetrate a water or oil cavity, anti-sieze otherwise. I don't know that Grade 8 are any harder to drill. Might be confusing hardness with tensile strength. Metallurgy is complicated.

Yes, we get that 72Dart6pack has a V-8 and enjoys trolling the slant forum. I have a slant, SB, & BB, enjoy all and the people who own them. The FMJ forum might need some elbows.