92mustang5.0

I just bought my grandpa's 95 f-150 xlt. it had just been sitting at my grandparents house for the past year cause my grandpa passed away last nov. My grandma needed to sell it so I bought it for 2000 to keep it in the family. my grandpa was a very good mechanic and he took good care of it but I have some concerns. it has 170000 miles on it. it starts right up but squeaks when running. I think one of the problems is the belt which is easy fix. the other is the a/c pulley. I cant tell the inner piece is suppose to move or not. I have a pic of what i'm talking about. my finger is on the piece that moves. the other concern is this big black box on the left side of the engine compartment. I think its part of the a/c as well. he had some kind of silver tape that had foam in the middle wrapped around it. i'm thinking it has a leak. I have a picture of that as well. I took the silver crap off cause it was falling off anyways. I also want to know what this rusted cylinder can looking thing is. I do have a 92 mustang 5.0 so everything looks to be somewhat familiar. any help would be awesome. thank you

92mustang5.0

I forgot to add that it's not throwing any trouble codes at all.