I have gas finding it's way in to the motor oil, I'm sure there are threads of this already. Here are my details . Sbc 350, just over 500 mile rebuild . New everything . Yesterday I went from an Edelbrock 1411 to a Holly demon 1901. 750 cfm to 625. The 750 ran okay but I definitely needed something smaller. The demon is brand new out of the box. Running rich off of my Afr gauge 10.5 and bumping in to 9 off idle. Exhaust is running black . I read posts already with most saying the fuel pump but since I just changed this carb then it may be more likely the carb. Something to point out, with the 750 carb the fuel filter would not hold full of gas. With the 625 the fuel filter does hold full gas. Suggestions before I buy a different fuel pump are appreciated .