7 inches of vac at 20 before TDC? If you're mixture screws aren't doing anything the primaries are open too far and you have bypassed the idle circuit. But first check your float level. I'd suggest carb removal, reset primary throttle blades for correct transfer slot exposure as a starting point. When you put it back on note where the cold idle screw is to put it back of you have to! Seat your mixture screws and then back them both off about 1.25 turns to start.Im not going to give a lesson on setting up the carb cause that info is readily available but I'd suggest you start with that. Make sure you adjust everything with the car at operating temperature. If you need more idle air you can start by opening the secondary blades a crack before you start drilling holes anywhere! Check that stuff first and it'll only cost you a base plate gasket!