Kinda pulling my hair out on a problem and would appreciate some input to get an issue on my flathead powered A running smooth. '37 flathead running electronic Mallory distributor and dual Holley 94s.. I have smooth idle and it revs fairly OK, I think i can detect a slight stumble but it may not even be there it is that slight. I replaced the spark plug leads which were old and the engine runs a little smoother but my main issue remains... The problem comes when I get the car on the road. Within 1/2 a mile it feel like it is going to die, I lift off the gas and the engine 'recovers'. At that point you need to coax it up the rev band, if instead you just hit the gas pedal and it will likely almost die again. Drive it into the workshop and park, get out and it revs fine once more from the carb linkage. I got it up to about 3k and held it there for 10-20 seconds, no problem. Didn't falter at all. As crazy as it sounds, it is only when the car is moving that there is an issue. Maybe gas starvation under load? Any pointers appreciated as this has been bugging me for weeks.