Nice AFR's below 3,800 b.t.w. - Am I correct in thinking that there's no advantage (ping or power-wise) in going richer than 12.7 ?
Edit:
If you've got the time/cash, you can plumb a knock sensor into the waterjacket (preferably in the centre of the head) and hit the dyno hard, timing light & knock alarm in hand. Then it's TWEAK TWEAK TWEAK with no fear of unknown detonation. JOY!
p.s. -pull some fuel outta that sucka: Leaner is meaner!