As long as it's feasible, I'd use permatex #2 on a STUD with a brass nut. Then if you tighten the fasteners later, you are not disturbing that thread sealer's seal.
This should be gospel. Those old studs were there for a reason, to seal up the water jackets and not have to disturb them. How many times have you had to extract these becasue they broke or you bent them in transport? Plenty.....
