Regarding the voltage to the dash gauges in 56, I think they got the full 12V. I don't see anything in the service manual to say any different, and I don't see any mention of a voltage limiter. The wiring diagrams also show full battery voltage going to the gauges. I checked the 57 and 58 service manuals, also no voltage limiter. I couldn't locate the 59 manual, and I did find the voltage limiter in the 60 service manual. So I could be wrong; I haven't been right yet today, but I think 56 -58 gauges received full battery voltage. Maybe also 59, can't tell until I find the manual. I tried to ask our resident expert Greg d'Leggatt but he sleeps late when it is cold. At the present temperature where Greg lives in Canada , he isn't expected out of bed until Tuesday. Bob Merritt (I hear it doesn't snow in Spain).