3M's the way to go...... NEVER USE SILICONE! Jeez, I hate that stuff on cars! (I'm a mechanic). Silicone fills gaps, but doesn't adhere to metal well, so it leaks. The previous posts are right on!
John Kennedy 1950 Suburban street rod Pics in the Gallery....... new site up! http://home.joimail.com/~kennedyjp/