Bernie, when the rig was on the dyno what did they use to determine engine temperature? You didn't mentioned that it was overheating on the dyno. I wondering if you have a faulty dash gauge. You haven't mentioned that the engine dropping into limp or shutting down which I would expect if the ECU detected a coolant high temp.
Also there might be two temperature sending units on the engine. One for the ECU and one for the dash gauges. The dyno techs may have been only checking what is reported to the ECU and not comparing the dash gauge.
It's a bit of a WAG (Wild A@# Guess) but at this point who knows.
