Make slowboy not so slow

[A//// Guy]

You replaced the water pump with a used one?.. Where did you take the block to deck it, and to machine the head? Or did it not need that, im assuming it wasnt warped.

Not sure what could have caused the overheating. Either water pump seized/broke, not enough coolant, blockage in the radiator or piping, or maybe the thermostat was stuck.