Tried jetting but still lean at WOT

Hopefully some of you guys can help me with a little problem I'm having. I went to the track on Friday to dial in my new combo, but no matter what I did I couldn't get the wot a/f ratios any richer than 13-13.5. I'm currently running 78 jets in the rear, but tried going up to 82 jets with no luck. I'm not quite sure where to go from here. Smaller high speed air bleeds maybe? I'd appreciate the input.

Specs:

QFT 650 dp
71/78 jet
rear jet extensions
80 idle air bleed
28 hs air bleed
.037 idle restriction (primary), .031 idle restriction (secondary)
100 needles
8.5 primary power valve
rear power valve delete
milled choke tower

255 lph Walbro fuel pump (67 gph)
5/16" fuel line
return style regulator
6.5 fuel pressure
Float bowl fuel level in center of sight glass

I've never dyno'd the motor but I'd bet it makes somewhere in the range of 350-400 hp.

Timing currently set at 18 initial / 33 in by 2500