[Ian in Mississauga]

Bill, Do not limit your potential market to the 32 Ford V8. The C4 was probably the most common 7/8-18 plug in use in the 1920's and early 1930's. High end cars like Auburn, Cadillac and Packard to Ford competitors like Chev, Dodge and Plymouth all used them. I saw this info in an old pamphlet put out by Champion.