The dash on top is from the 50-80 series big trucks. Look at both side of this dash there's two large circle's with the three lines joined together. These covers unscrew from the back. Then you replace the covers with the factory Tach,Vacuum, Bat-O-Meter or Air Pressure Gauge. The tach installs one the right and either gauge goes on the left. The stock Air pressure gauge went to 150 psi. Look through the Historical Thread in 1963 Cabs section there's a picture of the Air Pressure gauge. If you go to Gallery there's a picture of my dash with the Vacuum and Tach. These Air Pressure Gauges are easier to find than the Vacuum Gauge. This picture below is compliments of "daverod"
