I grew up around the best electrical shop in Nashville Tennessee back in the heyday of 8 volt batteries. Dad absolutely refused to mess with any car that ran one. They were a really bad idea in the late 1950's, and they haven't gotten any better with age. If you feel that you absolutely must run one, at least do the voltage regulator setting the right way- - - -9.5 volts. Any higher and the battery will boil itself dry, assuming the vahicle ever gets driven any distance long enough to bring the battery up to full charge.

An 8 volt battery is a solution looking for a problem for anyone who is willing to do the kind of routine maintenance a 6 volt electrical system requires.
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!