Buzzard Bait,

Years ago, I had the ASP 1.08 redhead and symptoms similar to yours. I also could not get a really rich setting on the needle with a pitts muffler, although there was no problem with the stock muffler. I also plugged one of the 2 exhaust stacks on the muffler, that helped. What I found was that in my ongoing effort to eternally tweek the low end for a lower idle, I had turned the low end needle in so far it was interfering with the ability of the high end to allow fuel into the carb. I backed out the low end needle a LOT and started to retune the settings. Surprise! I was able to get a "too rich" setting on the high end I couldn't get before. Maybe that is going on with yours, as well. [8D]

Good luck.