Crate engine overheated
Suggest considering the thermostat. Opinion is if it ain't Motorcraft, then rolling the dice.
Description sounds like the engine can't dump the heat, leading contenders are the pump for flow, the thermostat for restricting flow, and any air voids which haven't burped out.
Description sounds like the engine can't dump the heat, leading contenders are the pump for flow, the thermostat for restricting flow, and any air voids which haven't burped out.






