How do you send car parts to someone that's wanting to buy them? Help please?!?

Ok so my friend is trying to sell his car parts by announcing them on facebook and he found a guy that wanted to buy them,but the thing is the car parts are somewhat big and they can't be sent by mail so I'm trying to help him out by finiding out how he can send them through UPS or something.What does he have to do?? Please help. No rude comments please.|||the post office has flat rate boxes good for up to 70 lbs. not sure what your shipping but I sent a water pump before. If the part is really big then contact ups. have the weight and size of item and they will tell you how much.