A swagged 1-3/4" I.D. muffler usually requires either the original little tin 'shim' wrapped around the header, or some people cut what they need from a pop/beer can to make a little wrap-around gasket. My 99 is like that, and it doesn't leak. I got tired of skrewing with the leak between my 87 header and Dyna muffler, and just had my neighbor, who owns a large welding service, TIG weld it together. If I ever want it apart, my cutoff wheel on the die grinder will separate the two in just a couple of minutes. Meanwhile, I don't have to worry about developing a leak out somewhere.