In Class 8 Operation the operating range was governed between 1800-2100 RPM .. Shift both up and down at those points . I picked of Steel Loads at the Carnegie Mills in Pittsburgh , Pa. . After I turned he Corner onto the street . Lo and Behold . In front of me there was a Large Sign : " Truckers , this is a Hospital Quiet Zone" . At the Bottom of a hill BTW .. 903 w/Duals .. lol .. Hmm .. like the two stroke joke Detroit s were any quieter ? Yes ,, to be honest . This too would be the V/8 Choice for the two storied Falcon Thanx