John, I played with this on a Fox .50 I converted to Diesel. But, instead of putting a velocity stack on it, I raised the carb up 3/8 inch by putting an adapter under it that I made out of three 1/8 inch plates, not only did the fuel stop spraying out of the carb but I gained 200 rpm. I made the diameter of the hole in the plates the same as the venturi to keep the air/fuel velocity up.