Hi Bruce,
Regarding carb heat, my Performer RPM intake doesn't have the exhaust cross over. When I put the carb back on after going through it, I did use a different gasket, one that appeared to have some metal in it. I can't really go any thicker because of hood clearance with the air cleaner I'm using, and I don't have a hood scoop so a turkey pan isn't all that practical. I think the air cleaner is probably a big contributor, it's a 14" that wraps down around the carb pretty closely trapping engine heat. I have an H&S to try but had heard they are restrictive even with a K&N filter. I have a hard line from the pump to fuel log also, I wonder if a braided line would keep the fuel any cooler?
Thanks, Chuck
