VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 AC spark plugs

I have some NOS AC spark plugs type B and type C. Can anyone give me the proper aplication?

The Type B "Buick plug" came out in 1925 to directly replace the Titan Long 7/8 and was used up to mid 1928 - where it was replaced in production with the Type Z plug. The B plug was continued for servicing the early models. These early B & Z [about pre 1930] were not label with a B or Z - just the box they came in. The B & C plugs that were so marked on the plugs were built up to about 1937. The B & Z plugs had the 1 1/8 hex while the Type C was the same long extention plug as the B, it had the smaller SAE hex. The C plug was never used on a Chev 4 - but will fit and has the same insertion length.
KenK

Thanks for the info.

Maybe... maybe not. Please see these photos.

My experience has been the "Z" plugs didn't have the "Z" on the plug until later production. If you look on the flap on the box there will be a number that is the last two digits of the year of production. All the "Z" labeled plugs I have in the box were dated '35 or later.

Chevy B;
I have the 'B' plugs in my '25. They run better than any other replacement plug that I've tried. If you have a set, then hold on to them. (or sell them to me) They are very hard to find.

Here's what my end flaps look like.

My AC spark plug chart show's 7/8 inch special type "Z" for Dodge "4", Ford- model "A", "Chandler Franklin ('27-'28), Packard 1927, Studebaker (Pres. and Com.).
Hope this help you out.

Keeping Vintage Chevy alive.

Bill,
Your plug was manufactured in 1934.