66 chevy truck man

Does anyone out there know what the resistance in a 2005 GM stock full size truck sender is? I know in 98 they went to what is reffered to as the GM 250 which reads 40E and 250F. The 05 has some kind of a reverse sweep because the more fuel you add the lower the # gets on my ohm meter. I know some of you guys are thinking just pull the fuel pump and test the sender. Well I would do that but that would require removing my bed to get to the custom tank. I cant drive it to the gas station and fill it all the way up because I am doing some front end work currently. I did however add 2 gallons of fuel and the reading went from 188 ohms to 167 so I am wondering if any of you guys know what the new GM standard is so I can know exactly what I need to do for my fuel gauge. Thanks

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