I've got a pacesetter longtube header, no cats and a 40 series 2 chamber delta flowmaster and at idle it sounds like a 5.0, Up to about 1600RPMS it sounds like a 5.0 and then the higher you get it the more it reveals its true self. We had a club meeting down here in southern Maryland and there was about 20 5.0 guys there. When I started her up everyone swore I swapped a 5.0 in there. I had to pop the hood to prove it to them. :thumbsup: