Had a 60 cfm on a 550 with 6.0 power stroke. After using it a couple years blowing combines and changing tires on side of the road we started having EGR issues from carbon deposits from the constant idling running the compressor. Had to pull intake manifold 3 times to clean it. 
only mechanical issue was it would throw the compressor drive serpentine belt randomly which would take out main engine belt. Always had to carry both belt in the truck to change on side of the road. It always happened in the rain or colder than heck. 
other than that it worked great. Made a lot of air fast.