Too much Carb for a 318?

Well, the 750 is to big. I would go with a 650 cfm. to start. On the calculations for your engines displacemnt, it shows you should have at least 598 CFM. To go to a bigger carb, I would run the car down the track and see if you are pulling a negative on a vacuum gage through the line. If you are, you can go to next bigger size carb and tune it from there.