PV33 Vee Drives Overheating
My Burns-Craft also has PV33s and they hardly get warm while I'm running although I only cruise at about 1500 rpm. They whine a little in reverse but they're silent in forward.
I agree with OHB. CHECK YOUR HEAT EXCHANGERS.
You can buy an inexpensive infrared thermometer at Harbor Freight for under $30. This is an invaluable tool to have when troubleshooting many engine problems. When I'm on a long trip I routinely go back and check the temp on the engine, manifolds, and transmissions to help avoid possible problems.