Another fine mess...75 Dart Swinger...

Well, after a month of trying to get the tuning on the carb perfect, I finally got it. I had a hesitation anytime you cracked the throttle blades, high or low rpm. I bought a wideband Air/Fuel meter, and fiddled with all the adjustements, rod, jets, pump shot to no avail. FInally I posted the problem on Big Block Dart, and Jim Lusk came to the rescue, he suggested that the vaccum advance was plugged into manifold rather than ported vaccuum, which caused the timing to retard everytime I cracked the throttle. He was right, I made a 10 seconf change yesterday and it worked! Problem solved! Thanks Jim.