i found out by calling Jy's all over looking for a muffler for my regal. found a yard with a gp in it, had them cut it off, when i got there it was off a factory cat back, the guy told me over the phone it was clamped and they would cut the pipe past it.

i got there it was welded to the pipe, and no wheres near round, so i had to pass on it, as i have after market pipes already. which are very round at the ends. the 2 will never clamp up, not ever.