idle problem with long duration cam

11 to 1, 10 inches of vacuum, 170lbs cranking...you should have excellent drivability. No you wouldn't see any improvemnet with a vac. carb over mech sec's. with 11.0 to 1. Should be strong everywhere. Rumblefish is right. If you seek better idle quality..try one of the new shorter, hi lift cams. (less overlap). I like them because they work well with ported heads and pull good down low. 305 is long for the street. Keep us informed as to your progress. Terry.