Actually the Gonkulator likes that idea:
Torq 296 at 3500
Powr 255 at 5400
2.24
9.74 at 72.6
15.15 at 90.5
Gain of .13 sec and 0.9mph without going to a bigger cam.
I dont know the ins&outs of milling a GMC head but if doable (valve clearance, thickness, cracking etc) this seems a good next step.

PM sent on the timeslips thanks!