Damn I bet that was a bitch to diagnose. I agree, check your head bolts. Retorque them first, just to make sure they arent leaking b/c of a loose seal. I also had a head gasket go on me at the dunes, pissed me off I didnt know WTF happened at the time, but experience goes a long way!! I could of reammed on those head bolts and saved the weekend!!
Good luck man, overheating issues blow, but a combo of super rich and 100F at 2MPH could easily equal overheat.