I was talking to Gentry (1 of the owners) @ Auto Instrument and here's how he explained to check all of the gauges on a Mopar cluster....I should say it was my Ralley cluster..Your gauges all read the same E 1/2 F
73 27 10 ohm
thats the scale for all the gauges,oil temp,etc.. they all read the same Ohms the best way is to get the tank empty and pull the sender wire and put you meter on the term.,turn the key on and it should read 73 ohms,then add gas to 1/2 and you should be at 27 ohms,then fill it and you should have 10 ohms.This will be the same for oil press.,temp. Like first start(cold engine) up oil gauge should read 10 ohms(high pressure)and 73 ohms for temp.(cold engine)....and so on until you get the right readings, THE BIGGEST problem are mis-matched senders to gauge cluster...but here's a way to check to sender vs.gauge....I hope this helps you can PM if you need more info....