Thanks Rob. That sounds like a good place to start. There Is guy here locally that I used to haul with that just might have a service manual. I better give him a call. My old truck does sound good, it has dual exhaust with a set of Dynaflex chrome muffler stacks. Brings back a lot of memories of riding with my dad in the one he drove. As far as parts go for things like that oil cooler, and head gaskets, where is a good place to buy them? Will any Mack dealer be able to get them for me?