looking at a mint 2000 f150 XLT with 4.6l at 220000 KLM and want to know how reliable and longevity of engine.

 

Without knowing the vehicle's maintenance history , it is a shot in the dark. From a different perspective, what is the reason for selling the vehicle?
I for one , don't know too many folks that want to sell a "good" running vehicle.You might have an experienced "person/shop" check it out for you.