Carl,
I have had some luck using 767 with .010 trimmed from the trailing edge with red/purple and about a 1.52 - 1.65 r/o based on track lay out. I trimmed the trailing edge for heat reasons and it seemed to keep the motor stronger in the 4th quarter.

Trav Schreven peeled my stickers over the weekend with an F brush, full, red/black with a 1.48 roll out to my 1.52. Trav has more Nat's titles then I do... so take what I offer lightly.