I bought a 1992 indy 500 engine for my xcr 440. It has the xcr exhaust and carburetors (34 mm) on it. The engine was an efi model so i had to put a fitting on the engine that lead to the fuel pump. What it does, is it'll run fine then at WOT it will start bogging down after a little bit. Real bad though then it runs like crap. I don't get it because it runs good for a while then cuts out. The jetting must be good because the spark plugs are a perfect dark tan color. My thought is that the fuel line is too big that goes from the fuel pump to engine. I could only get a 1/2 inch line to fit on the fitting. I think maybe i could get a 1/4 inch line to fit on it and i think maybe thats what i need to do. I'd be very greatful for any advice.