10-31-2006, 06:27 PM
It was 1955 for Chevrolet. I believe GMC went with them.
As I mentioned earlier, 12V will damage accessories but it's unlikely it will damage a starter motor. In the 50's, our "starter packs" were gasoline engines running an alternator that pumped out around 14 volts. The only time we had problems, as I recall, was when the battery being "jumped" was frozen - i.e. discharged and left that way for a while in below freezing weather. Pumping the amperage the starter pack developed, at 12V could and sometimes would cause the battery to rapidly overheat and burst the battery case. Of course, those who thought it was cool to work on their cars with a cigarette dangling from their lip sometimes saw a similar response even if the battery wasn't frozen. As always, YMMV and I retreat to my suggestion of pushing the vehicle unless it was a rare automatic transmission model.
As I mentioned earlier, 12V will damage accessories but it's unlikely it will damage a starter motor. In the 50's, our "starter packs" were gasoline engines running an alternator that pumped out around 14 volts. The only time we had problems, as I recall, was when the battery being "jumped" was frozen - i.e. discharged and left that way for a while in below freezing weather. Pumping the amperage the starter pack developed, at 12V could and sometimes would cause the battery to rapidly overheat and burst the battery case. Of course, those who thought it was cool to work on their cars with a cigarette dangling from their lip sometimes saw a similar response even if the battery wasn't frozen. As always, YMMV and I retreat to my suggestion of pushing the vehicle unless it was a rare automatic transmission model.