One more for good measure. The stock muffler on the header proved to be problematic. The free flow of the exhaust down the 5/8 inch header is now backing up where it joins the stock muffler due to a size restriction. Heat builds up at the connection and is subject to failure. I guess I need a small can muff to make it right. The open header is great but exceeds decible limits at the field. The exhaust routed this way leaves the plane goo free, which is a big plus. Joe