locked down motor question

alright i bought a motor for my car but it was locked down but i only paied 200$ for it i was wonderin what u guys thought about unlockin it we put tranny fluid in it and let it sit for a few days and it unlocked but should i risk putin it in my car? my cousin told me that it would proably just fuck up again in a few months just wonted to ask u guys appinion

Boat anchor. Or rebuild core.

go buy some pb blaster, spray a bunch in there and let it sit for a while, should break loose and get rid of the rust.

it is broke loose the question is should i risk putin it in my car and it fuckin up later down the road