Late-style SB thermostat housing...those dimples

Well, what actually went down was that I installed this thing as-is, with sealer against the intake, then a new gasket, then the thermostat, then the housing. And, it leaked. Not while running, but each night when it cooled down it leaked. So, I took it off, ground the dimples, sealer on both sides of the gasket, reinstalled, dry as a bone. Live and learn.