As far as carbs go, what kind of differences would there be between the 650cfm vs the 750cfm? Would th economy be noticeably better with the 650cfm? How much power would a 750cfm gain over a 650?
Bigger card doesn't automatically mean worse mileage
A bigger carb is less restrictive you could make an argument that too restrictive of a carb can kill mileage through pumping loss.
