mechanical @$$hole
 

Picked up a 89 f250 with a 5.8. Done some minor work"" so I had to flush the entire fuel system. Runs like a beast, now my issue is that I keep shredding belt, its squealing bad. Change the tensioner and ac pump so its still doing it it pulls the belt up on the back of the pulleys and shreds it I'm stuck any ideas?

One of the pulleys is binding or is way out of line.....

Try putting a straight edge on one of the pulleys to see if it lines up with the next. You may have to shim your alternator or PS pump to aline with the crank and water pump