A friend intends to compete in TSM at the National's this year and is reasonably convinced that the 3 1/2 " down pipe has an advantage over the 3" down pipe when running in the high 9's low 10's. Word is that up to 25 hp was observed on a chassis dyno. Terry Houston was producing them some years back but is no longer. Red Armstrong had talked about having some built but I believe that too is no longer. ATR does not build a 3 1/2 " downpipe. Does anyone know of a vender who sells 3 1/2" downpipes? Preferably stainless but mild steel will be ok. Thank you.