I don't even run a radiator or a water pump on a test run. Just connect a garden hose to the water pump inlet and control engine temp by the flow rate with the coolant running out of the thermostat housing, without a stat installed. The wrecking yard owner across the street from my shop in California back in the 1970s taught me that trick. He would run engines for a couple of hours or more that way with the engine strapped down to a forklift pallet.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!