81SC hesitates at 2000 RPM

[SP2]

Hello. My SC had a broken distributor a few months ago. Before it broke, John Walker helped me set my CO and my idle was ok at about 1000 RPM. It is an engine that I souped up myself with new 964 cams and SSI's and a complete reseal. A month later, the distributor stopped advancing and JW loaned me an older SC distributor. The old one only has a vacuum for the advance line, and the correct one has 2 vacuums for the advance and retard lines. The old distributor worked right away, and the only problem was a high idle at 2000-2800 RPM when fully warm.

I finally found a "new" correct distributor and installed it last weekend. It seems to work pretty well and I adjusted the advance at 5000 RPM to 38 degrees. But irrespective of the temperature of the engine, it seems to do this hiccup at 2000-2400 RPM as I begin to accelerate. It doesn't seem to matter if I am lightly accelerating or giving it the gas. After 2400 RPM it revs smoothly.

Just trying to figure out how I can fix this. I am not sure if it is the used distributor, or my timing. The distributor cap and rotor were new at the time of the rebuild, as well as the spark plugs. The cap and rotor might have been damaged with the broken distributor, but seem to work ok at higher RPM's.

Of interest, I took the car with the other Pelicans here for a dyno day Saturday (with the older distributor) and my first two runs just puttered out with a little pinging and I blew out a bunch of black smoke. The guys told me I had alot of carbon build up and I should start to "drive it like it is stolen." The third run had a little pinging but at least there was a recognizable HP and torque curve and it put out 169 HP. Could my problem be related to the carbon build up?

[SP2]

Well, I can now answer my own question. I visited John Walker today and he asked me what I set the advance to. I said 38, he said 34. It now runs perfectly. Thanks John.