12 volt - negative ground
Chevrolet - negative ground
GMC (6 volt)- positive ground 193? -1955?
Push starting should be an option, even with a dead battery as long as it is not totally depleted.
Good excuse to get yourself one of those portable battery jump starters. I like the one with the built in air pump. These are about $65 at costco. When you need one. Priceless
Good luck!
