Without removing the fuel sending unit. Is there a way I can figure out with the factory oHm range is of a fuel sending unit. I need to hook up a fuel gauge to my 72 GMC Tow Rig that I put the Cummins in. I'm using the factory 1991 Dodge Diesel fuel tank and hoses and sending unit. I know it will not wire in directly to the GM gauge since the oHm reading is way different so I have to buy a seperate gauge. I just can't figure out which oHm reading one to get. I found the one for the Dodge fuel style but it does not cover the diesel. Anybody know where I should begin to look? The guy at Summit racing said all Dodge/Chrysler products are the same. I find that hard to believe. I cannot switch out the sending unit. The Dodge Diesel one is about 7" in diameter and held on with a hose clamp. I really do not want to have a custom one machined just for a chevy sending unit.