I am using the stock H-pipe exhaust, stock Cat pipes and OBX shorty headers on a LS1 with a Trick Flow cam and header upgrade. I am having exhaust fit up issues where the Cat pipe is contacting the bell housing on the passenger side near the starter. I pressed in a flat on the exhaust and can pretty much get the pass side to fit well between the headers, Cat pipe and H pipe, but on the drivers side not so much. When I connect the cats to the header, I get a v-gap at the Cat to h pipe flange of about 1/4”. Pictures attached. Anyone have any thought/experience here on what the issue could be?
Mine came together fine with the gaskets installed, but I used the factory Vette manifolds as that was what the cats were designed for. You may have to see which flange is not flat and go from there.
I've only installed the FFR exhaust on one car....the very first car I built before the Kooks system even existed. I do remember that I could not get it to be centered thru the rear of the body and ended up using 2 gaskets on one side and one gasket on the other side to essentially "shim" it over where I wanted it to be.
Shane Vacek
VRaptor SpeedWorks, LLC www.vraptorspeedworks.com
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