I already have one Gardner Denver compressor with a Perkins Diesel. It is a great machine. I have the opportunity to pick up another GD but this one is gas and I'm thinking it is a 175 cfm. Mainly I am wanting info about the unit but the owner died and who knows if the seller will find manuals. Numbers/info I have found off the machine: model # spfga 664466 1974 (thinking this must be the year) N.B. 51871 ser 10871 H.D. 175 (why I think it is 175 cfm) It fires up and runs very well has around 2200 hours I'd appreciate any information you all might know.