I'm fixin' to put the top end of my 97 M900 back together (cylinders, head, etc) and am wondering what type/kind of goop I should use on the aluminum base gasket. My Haynes manual said I should use some, but it isn't specific as to what type/kind. Anyone have any favorites? I've got black, gray, hi-temp black, and some old fashioned Permatex (both the black non-hardening kind and the rust colored kind that hardens). Recommendaitons?