You need to wire up the coil properly using the ignition resister. There is a good write up in today’s news. Ignition wire(hot) needs to go to resistor, then to coil. Wire from side terminal at starter to coil also. This wire provides 12v to coil upon starting only, then reverts to 8 or 9 volts being fed from resistor for continuous duty. Make sure you understand this operation.

A one wire alternator does away with the voltage regulator.

You can also add relays to reduce load, thus brighter headlights, etc. for large loads.

6 volt vehicles have heavier wire than required for 12 volt systems, thus that is a bonus when changing to 12 volts.

Read today’s comments, all spelled out there.

Ed

'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.