I'm no guru but looking at the advance curves and your top speed reductions suggests that curve 7 may be simply too much advance for your setup. Dyna says curves 6 and 7 are for engines with modified exhaust and jets. Are you running premium to avoid detonation?
BonS, I was running premium gas the day I ran the test but it runs just as well on 87 octane. What I think is happening is it is starving for gas...I have the rev limiter set at 8000 so I know I'm not turning that many rpm's at 131 mph....