6v to 12v swap

[sneakysnake]

I swapped a 6volt sys to 12 volt and everything went fine until when you would turn the key off the alternator was back feeding the ignition and not shutting off.
I went to the search and found that I need a resister on the #1
or switched wire. my Question is if I walk into auto zone and request this will they have a clue what Im talking about, It wasnt easy getting the other stuff(coils,ign resisters,relays,sol) Is there a part # to ask for so they can see it on their computor or they wont have a clue. Thanks