found an engine! now what else needs to be checked/replaces while new engine goes in?

[Dropt72Shortbed]

allight found a chevy dealership who will sell me the goodwrench 350 motor for $1420 + $100 core charge, and ive got a guy installing it for $500.

now what else should i be checking or replacing while the new engines going in? i was going to have the radiator sent out to be pressure tested etc, getting a new water pump, what else do you guys suggest? i just did a tune up on the ignition system (new plugs wires coil cap rotor) so im thinking im only going to buy new spark plugs since theyre probably gunked up with oil in the two months theyve been in.