Ah, Grayhawk, sir, you're making an assumption based on facts not in evidence. I have a picture taken of the panel in my 177 that shows operation at top speed under advertised standard conditions - 59 degrees, dry air, 0 MSL. That's right - 200 feet AGL in Death Valley :-). Surprisingly, it was within a couple of knots of the advertised top speed.
Gary Casey
I do have a problem with your sea level speeds as the aircraft would have increased drag from the sea water.
Grayhawk