My freind is gave up trying to figure his '70 Cuda 340 problem out and came to me, I'm stumped. after if gets hot if you idle it or shut it off and restart it it will fumble and ping a little bit, it doesn't die but it's runs funny until it gets reved up a little. I noticed that the fuel filter is empty while it's running, not low I mean all you can see is a TINY trickle in the very bottom. it has a new fuel pump and Edelbrock AVS , so we pulled the suction line and it's clear and the tank is venting good, it an empty filter a problem? the fuel lines are routed well away from the engine so I doubt vapor lock. so we unhooked the line to the carb and pulled the coil wire to crank and see if we're getting gas, when it's hot it keeps wanting to diesel backwards with the spark disconnected. we checked the timing it's fine, could he need cooler plugs? a better grade of gas? it only does it when it's hot, it's drivable but irritating.