Hello, I'm certainly not expert. But all i've used is Fel-Pro, probably because its all i've ever had ready access to. It's easy to use each one twice. No leaks, No problems. Cheap. Easy. Fast. -- Best regards, Bill L. mailto:pythias at pacifier.com '66 Sprite MKIII HAN8L49403 "the red thing" Copper wire: Invented by lawyers arguing over a penny.