slant is running hot

the last annual inspection on ths car was 1981 so to the best of my knowledge it has been off the road for a really long time. i think the prev owner was trying to get it road worthy as it had a few new parts when i got it. will a heater core make a car overheat? with engine swaps i never bothered with stock rads just went right for the cheap aluminum ones. im thinking of pulling the top tank off and making something to clean all he tubes out. as for the water pump, i was thinking of pulling iot off to inspect it. think is possible the blades are gone?