Hi, I Have a 68 FE390 with a Holley 780 carb with vacuum secondaries. The carb has just been proffesionally overhauled. When the engine has warmed up and under steady rpm the car starts to sputter but when I give it some gas no problem, good acceletation and no sputtering under load. When I slow to turn a corner and when accelerating out of a corner the car sputters and cuts out under acceleration. When stopped and revving no problem. Any Ideas?