Lower the float level a little, and/or go with a slightly leaner main jet. The high speed system is too rich, and it's not adjustable like the idle circuit. You'll need to find someone with a 4-gas exhaust analyzer to get an accurate reading on the high speed mixture. One of the ones I have in my shop can be operated on 12 volts DC, so I can actually monitor mixture during a road test under load, as well as high RPM operation with minimum load in the shop. It's a good idea to check both, so you don't end up too lean, and burn pistons and valves in a lugged-down situation.
Jerry
