Nice truck! Like that color.
The difference between the later model senders and the old ones is about 14 ohms.
My truck has a 195 degree thermostat so used an infra-red heat gun, shot the top radiator inlet tube when the thermostat opened, put a potentiometer in the sender wire and adjusted the reading to middle of the gauge for 195 degrees.
I was going to get all fancy and put a 14 ohm resistor in there but other repairs/improvements take priority.
One guy at a car show called it "dial a temp"
