Adding a Tach to a motorhome...
My grandparents recently purchased a 1978 Ciatation Bendix 31' motor home. It has a V8 454 under the doghouse. We clocked it at 60 mph, it gets 7.2MPG, its 109 dollars for 3/4 of a tank of regular. We want to hook a permanate tach up to it to see what RPMS its sittin at. My dad says a tach only needs 3 wires, one for the coil, one for the dist, then the light, or so he remembers. How would i go about hooking one up?