Re: f-150 '84 starting problem
A fresh battery will have at least 12.6 volts (1.2 volts per cell). Anything less than that, put the battery on a slow overnight charge (2-6 amps) and that should possibly raise her from the dead.
In order to determine if the battery is starting to fail, once you charge overnight, start the vehicle a few times and then wait 5-6 hours. Retest the battery. If it is lower than 12.6 volts, she's starting to fail. Go get a new one.