hmm .. you sure about that? The data I have found shows that a '66 is 0-90 ohms http://www.hotrodhardware.com/index.cfm/page/ptype=product/product_id=251/prd251.htm http://www.classicinstruments.com/index.aspx?documentID=fuelgaugesandtank https://summitracing.custhelp.com/a.../~/measuring-a-fuel-level-sender's-resistance
If the gauge is original to the truck the sending unit should be 90 ohmns, GM changed to 90 ohns for that year, `65 and ealier were 30 ohmns, when the exact date was in `65 late model year I don`t know.
I have an Autometer 0-30 ohm gauge in my truck also. What did the relocated gas tank you are using come out of?
Relocated Fuel Tanks I've been looking at rear mounted , behind the rear axle & between the frame rail tanks for many years using Brand "F" Econoline tanks , Sunday I was looking at a nice bagged 1960 3100 and he used an old IHC Scout tank , it's compact and was easy to mount in front of the rear end , between the frame rails , using the Scout's tank straps . he said the sender worked with the Chevy fuel gauge too .
I used the tank kit from a local supplier..same one our host offers. Worked good bolted right to the frame rails. I believe it's the suburban tank.
Is it the extra capacity tank? Got any photo's? The tank I bought for the back of my truck didn't have a sending unit so I bought one from Brothers. Did your tank have the sending unit included?
sorry I don't have any pics...but yeah it came with a sending unit. Had to cut the neck off about an inch, plug a couple of vent holes..except the main vent. Capacity is 20 gallons...and it doesn't go below the pumpkin...it's actually about 3 inches above rear end. I'll try to post pics...I have any much luck posting on here...I know I have a pic in my phone