old gauges go what do i need
 

i have a 02 cummins 24v just got a air dog2 150 adjustable pressure any way i took off the filter and pump changed the fitting going into the injector. my mechanical gauge connected to the fitting i changed going in the injector pump what type of gauge i need now or where do i hook it up? do i need to go to an electrical fuel pressure gauge? my original gauge is black everything with white numbers and a red arm what you have for me?

airdogs have a port on the LP to get the fp reading. ive no seen anyone runa mechanical gauge back that far though