I have a 1955 F100 and I need a new ignition switch I found a 1956 ignition switch but before I buy it I want to make sure it will fit into my 1955 dashboard. Can anyone tell me if the two are interchangeable?

 

Try posting this in the '48-56 F-100 & larger trucks forum.
I will also suggest that you may benefit from buying the HiPo parts catalog that is available on eBay.

 

I looked them up. They were different part numbers. '53-55 used FAA-11572-A and '56 used B5A-11572-A. I suspect that the contact ratings -might- have been different. Somebody else can comment as to whether or not they fit and function anyway.

 

I have had a '56 switch in my '55 for several years. I don't remember if I
had to do a bit of minor hole enlargement or not. I know I did on some of the
dash fixtures, but none of it was difficult.

 

Your asking about putting a 12volt switch into a 6volt system of the 55. Have you converted to 12volt? If not, go with a 53-55 switch - they are easy to find.