Have a 76 B that has been taken back to 2 HS4s. Had a new pacesetter exhaust I put on a few months back for 68-74 MGB, like the one that had been taken off. Exhaust came apart at the weld of front muffler (?). Should I be using the exhaust (pacesetter) for 75-80 instead? If so, what kind of installation problems would I encounter?