The optimum power happened with #142 main jets using the oxygenated gas. This was a three sizes larger than the optimum main jets using the leaded gas. This is as expected.
The Stage 3 spark advance curve is the one used my most race engine builders. Average peak torque for three runs was 71.1 pounds-feet. The Stage 4 curve is 2 degrees advanced from the Stage 3. It gave a 3-run average of 70.9 lbs-ft. The Stage 5 curve is 4 degrees advanced from the Stage 3. It gave a 3-run average of 69.7 lbs-ft. The best policy is to run the most retarded curve that gives decent power. This is the Stage 3 one.
Average power is 87.2 with the 142 mains and the Stage 3 curve. ERC suggests, and I agree, that something is holding this motor back so it cannot take advantage of the oxygenated gas. They have some suggestions. This winter I will implement them.
The next step is to figure out the density altitude in the dyno room when the jetting runs were made. The climatic conditions during the three pulls are listed on the printouts. Avg temp is 91.4 degrees F, uncorrected barometric pressure is 30.22 inches Hg, humidity is 12%. The Airdensityonline website has a calculator. Using it, the density altitude in the dyno room was 1,853 feet.
The general rules of thumb for Keihin FCR's are to decrease the main jet one size for every 2,000 feet increase in elevation and to decrease the pilot jet one size for every 4,000 feet.
The average of the three highest density altitudes on my time slips from B'ville are 6,590 feet, the average of all density altitudes is 6,020 feet, and the average DA of the lowest three is 5,390 feet.
6,590 - 1,853 = 4,740
6,020 - 1,853 = 4,170
5,390 - 1,853 = 3,540
Decreasing the main jet two sizes and the pilot one size should be ideal. What I will do is to decrease the main jets one size and to leave the pilots alone. It is better to have a slightly rich mixture in an air cooled motor. A little bit of extra fuel cools them down some.