We discussed the problem a few days ago of an original ammeter pegging out when used with a high-output alternator, and more or less agreed that an extra shunt around the ammeter is a good idea. Since the original generator could barely deliver 25 amps to a 6 volt battery at full output, the ammeter will go off-scale for a short time after starting if a high-output alternator is installed. To avoid this situation, and possible damage to the ammeter, part of the charging current needs to bypass the ammeter. NAPA and several of the online parts stores offer such a shunt.
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!