Personally, if I am going to use a car frequently I will convert. By the time you buy the 00 cables you should be using, the larger 6 v battery your already into 150 bucks. Then after you have let your car sit for 2 or 3 weeks and go to start it you usually grind and grind thinking your out of fuel in the carb- but not so you charge it up overnight and then amazingly it fires right up- at lest that is what happens to me. Then it dawned on me -" If you think it is a fuel problem check your ignition system" -Wendell Mims 1935- 2004-
I am convince that 90 percent of the hard starting is ignition related. On the old 6 volt systems all must be very near perfect to have her fire after sitting. I have an A model 34 plym 50plym and 48 taxi all converted and no problem starting Have varying degrees of trouble starting with the remainder.
That 12 volt shot to the coil from a ford type starter solenoid really is fantastic in getting them to fire
Just my thoughts
Lou