Denny, it is a '56 235 hydraulic lifter engine out of a car with a manual transmission according to my figuring. I put a mr. Gasket paper element air filter on it (which is a very poorly designed piece of equipment) I had to run a bead of silicone around the base to plug up the gaping holes left by the poor fit on the carb. I have jacked a couple degrees of advance into the timing, but that did nothing for the stumble, I'm debating on whether or not to put it back to zero.