I doubt that newer senders( 12V) will match your stock 6V gauges. One solution is to get a temp gauge from a 70-80's Ford car or truck with the sender. Believe it or not that newer gauge movement will fit inside your stock gauge case exactly. Only rub is you'll need a 12V-6V reducer. I use a Ron Francis VR-1. Remember, even thought the gauges are from a 12V vehicle the gauges operate on about 6V as your 6V car's gauges operate on about 4V . Some of the newer cars have a small reducer attached to the gauge, a small box about 1/2"X1/2" X1". As described you'll have newer movements and senders but I'm not sure if this will work with double senders if yor're running a F/H .