I have / had a fish tail straight pipe with an 8 hole baffle in it . I put the bolt in one of the slots at the head of the pipe, tight fit. then made a  filler shim out of flashing metal, clamped it down and put a polished hose clamp on the middle part.

It held fine but was way too loud. Too bad because it gave me a lot more power, looked good too.

I'm still looking for a good sound  that will keep the neighbors from pulling out the torches and pitchforks.

Let us know how it works out. I am fascinated with the sound of thumpers and love to mess around with mufflers.