12v or 6v system?

[Jmsanch]

I wanted to say thanks to everyone for your advise with getting this old car running again!  There is one area I'm still not 100% sure on, the electrical system.  Owner says he used a 12v battery when it was previously running.  I really don't see any evidence of this being upgraded to a 12v system.  Not to mention there is no way to securely hold a 12 battery.  It just rests on the distributor cap.  I see the voltage regulator, and there is a label marking 12 volts.  But I still see a generator, and the lights are marked 6 volts.  Digging further I turn the lights on, and I'm getting 12 volts to the lights.  So clearly nothing is stepping down the voltage to 6 volts.  I wanted to see if the engine would even turn over with 6 volts, but I don't have a 6 volt battery for this car, and 6 volt batters are not readily available here.  So we took the 12 volt battery out, and connected the leads to my charger, set it to 6 volts and tried to start the car.  It didn't even have enough juice to turn the engine.  Slowly brought the voltage up to 12 and the starter finally started to turn.  I really don't want to fry the system given how hard it can be to find parts.  The coil is 6v and it def gets hot after a while.  We actually ended up frying another coil because I left the key on.  Not sure if that's because of the 12 volt battery, or just common practice not to leave coil key on when the car isn't running.  I think we should upgrade to a true 12 volt system, but I would like to have some understanding regardless.  Or we were thinking the voltage regulator could be bad?  

[GARY F]

i dont know where you are located or the year of the car, but a farm supply will have a 6 volt battery, or here in the states some are called Tractor Supply. If all connections are real clean a 6 volt will turn it over nice.

[Jmsanch]

Located in Northern Illinois, car is a 1940 Pontiac Deluxe.  Ok thanks Ill look at the tractor supply direction.  There are a few close by.