Hi Matt, Oh, to answer your question, I'd use the steel ones EVERYWHERE. I don't like using dissimilar metals in cooling water because you tend to get galvanic corrosion at the brass-steel interface. However it takes a steady hand, an accurate eye, and a "calibrated" whack to get the steel ones to expand properly. The brass ones don't require as hard a blow. To do this right without all the practice the guys at Chrysler had, I machined a round head punch with about the same curvature as a ball pein hammer and hit that with a three pound sledge. NEVER use a ball pein hammer itself for this "punch" though because it's very dangerous to hit two hard hammer faces together. Kurt Kurt Greske ( kurt_greske@xxxx )