On my '76 Hondamatic 750A, I was finally able to drill and tap out the second, rounded over bolt of the muffler clamp. (My first drill and tap, btw. I am so proud.) Now, I am trying to remove the actual muffler and it won't budge. Is it welded to the 4-into-1 headers? Is it likely to be just rust holding it on? Should I try, ah, heat? Just more banging on it? Grab it with a band clamp and yank? Any suggestions greatly appreciated.