Hi there. Looking for direction. My fresh 454 run great pulls strong under even slight throttle. No missing no stumble from idle to 4500 rpm. HOWEVER if you are just light on the gas and maintaining at 2300-2500 it feels like a sputter or miss. As soon as you put a little more load on it it's smooths right out. Any thoughts of what i may check?

FYI - Its a 454 flat tops, iron oval port heads 219/188 valves, comp magnum 280H Cam, Eldelbrack RMP Air Gap, Holley 750 Mechanical 2 feed. Primary jets at 75, secodary 80, power valve 65. has full 13" vaccum at idle, no apparent leaks.
MSD 6AL with MSD Coil and Distributor. Timing 32 Deg total advance.