He was mentioning something like that, that the neck down needed to be where the paint no longer burned off the exhaust was his explanation. You did a much better job of it. I'm just concerned that it is not far enough back and too narrow. I posted the specs above for the engine. I have 3 step headers on it: 1-5/8 to 1-3/4 to 1-7/8 into a 3" collector.