Just rebuilt my 390 fe engine and it dies when going into drive, I have to feather the gas to keep it going. When it does idle, it barely accelerates from idle and it'll even pop through the carb until it gets some rpm and then it goes fine, it would drive like normal if I never came to a complete stop. The engine is a mild build with intake, carb, msd ignition and hei dist, and it has a camshaft that gives it some noticeable idle. Even idling at 1000 rpm, it still dies. I've looked at timing, vacuum leaks, mixture screws, nothing changes it. thoughts anybody? the engine ran fine before the rebuild and it had the same camshaft and mods.