6volt to 12volt conversion on a 53 Ford

[53INGY]

I have several questions on how this conversion done properly I am looking at a car to buy with this conversion I understand they are changing the starter motor but I wonder about horns guages blower motor overdrive controls etc.the lights are easy change the bulbs I wish they the seller had left the 6 volt system alone would appreciate input on what to look for if go ahead with a purchase Thanks Ford barners