I had my 53 Merc on a Pertronix module with 6vlt Pos. ground for years. (from the Pit Stop) Ran great for years with a stock Distributor. Then when I changed to 12 volts, I just moved to a Pertronix 12 volt model (also from Pit Stop). Always kept the points, cond. etc. in a bag in the truck, just in case. Never had to use it though. Make sure and tighten the advance springs on the dist. if you stay stock with a flathead distributor.