ya need to be double checking the fuel lines by putting them under water, plugging one end with your finger and blowing in the other end, flip it around and do the same thing. Do it with both fuel lines. Do the same thing with your fuel tank, if the lines are good, place one of the lins on the cap inlet and plug the outlet with your other finger and blow gently looking for air bubbles, then blow alittle harder watching for air bubbles. If there's no leaks after that, then you want replace your exhaust manifold gasket (they're cheap with it), I suggest the HPI big block exhaust gasket, they hold up very well. Double check the exhaust coupler, take it off clean the area of the pipe and manifold where the coupler goes and rough it up a bit with some sand paper, put new 1/8th to 1/4 wide black zip ties and get them as tight as you possibly can. Check your carb gasket, get high temp copper gasket sealer and put a light film on the neck where the gasket is. check to make sure your glow plug is seated properly and not stripped, spray nitro fuel or WD-40 around your head gasket and glow plug, Nitro fuel will make it rev up, WD-40 will make it bog down. Check and make sure there's no air leaks around the back plate, clean it and put a thin layer of gasket sealer around the area where the gasket is. That should pretty much cover everything.