Old 1960's AC racing spark plugs

[JoeC]

Anyone remember these AC plugs?
The are from 1960s and supposed to be a AC racing plug

the tip is a small diameter like some of the modern plugs

no numbers on the plugs but has 541-CAG on the large box

I couldn't find a listing for that number

[Jon Mello]

Joe, those look more like 1950's era spark plug, including the packaging. In the '60s they had the Fire Ring type with the 4 green stripes around the upper part of the white insulator. I don't know what the application is for the ones you posted.

[JoeC]

thanks for the reply Jon

when researching them , I read where the 1950s plugs had smaller diameter porcelain and didn't have the ridges in the  porcelain but they didn't say what year the ridges came out

they could be late 1950s

thanks

[Jon Mello]

You're welcome, Joe.

It's just amazing to me that these have no identifying numbers on them. Once they're out of the package and installed, how are you supposed to know what heat range you've got?