71 Dodge Dart Swinger in England

Heres a schematic and pic of how to wire up a solid state voltage limiter IVR (instrument voltage regulator) for your factory electric gages. These run off 5v and use a vibrating points type limiter to drop 12v to 5v. When the stock limiter fails closed, the gages peg, when it fails open, they drop to the low end. Your factory water temp, fuel level, Oil pressure gages are the ones that use this limiter.

Mine uses ring terminals because my original limiter was located inside the gas gage. Your darts cluster its a little metal rectangle box on the back of the circuit board. You can probably use male spade connectors and plug it in. The nice thing is that for about $2 in materials you can solder up your own IVR

Hope this helps
Matt