I drove my 66 yesterday and the Instrument cluster went haywire. The fuel gauge mooved from a 1/2 tank to full. The water temp went from a good running temp to hot. The oil pressure went from good to high. All this happened in about three seconds. Help!!! Can anyone tell me what has happened ?

 

Sounds like your instrument cluster constant voltage regulator went out. It is located on the back of your instrument cluster and is a small block about 1" x 1 1/2". You can get one at Carquest for around $35.