I can only help you with part of it. The 6volt to 12 volt thing can be solved with voltage dropping resistors. Speedway carries them but you will need one for each instrument that requires voltage to make it operate, and you do not want to buy the inexpensive one of the two they sell. Gauges require one that will not spike voltage on startup, otherwise the gauge can be damaged during that spike period. The more expensive one cures that.

As for the speedo, and possibly the rest of the gauges, there are places like United Speedometer who can help you out with cables, etc.

That is the extent of my knowledge on the subject.........let's see what info others can provide.


Don