Lets\' see... I pulled the stock manifolds off yesterday check for crack's (none found) I place new manifold gasket's in. Start up the K5 exhaust leak is still there. Sounds a bit better but still noticable. I 've replaced the lead donuts, and added manifold gaskets. The only other thing it could be is the EFE valve ($100).. then my dad brings home the horse trailer and the trailer brakes don't work. Propably put in about 6 or 7 hours of work in this weekend,and still none of the things worked on work. Makes you go hhhhmmmmm....The beauty of being a K5 owner.