An 8 volt battery is a solution looking for a problem. Have someone who knows what he's doing adjust the cutout relay to 8.25 volts and the voltage control points to 9.5 volts against a fully charged battery with the engine running at 1500 RPM. Then buy a case of headlight bulbs. I'd choose to trash the 8V battery.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!