Extraneous information regarding 6v changeover in trucks:
Chevrolet trucks:
- 6v through the end of Chevrolet Advance-Design (1955 1st series)
- 12v from the start of Chevrolet Task Force trucks (1955 2nd series) - 6 & 8 cylinder engines
GMC
- 6v on 6-cylinders through the end of 1955 (beyond the 54/55 New Design Z-series)
- 12v on 8 cylinder Blue Chip series - late 1955
- 6v still on 6 cylinder GMC engines in late 1955 New Design Y-series
- 12v on all 6-cylinder GMC New Design X-series 1956 engines
Chevrolet cars changed to 12v at the model change in 1955.
