Denny I agree it is a little loud for my taste. I am running a 4 inch collector with a 4 disc muffler insert sold by a company called Car Chemistry. This winter I plan on pulling them out and looking at other options. And you're right, I have a Crane roller cam and all clearances were set up for minimum break in. I think it's ready for the track but first a couple of outdoor shows once the temp drops back into the lower 90's.