After using a spark plug testing machine at an airport that was doing engine annuals, I found that it doesn't matter what is "looks" like or brand.
You can go through a box of "new" spark plugs and only find a few that still work under pressure/high compression.
Too many people follow the rest of the sheep about parts.
Always remember that last years parts are not this weeks parts or next years.
That most parts are made by just a few makers.
When these cars were made, most of the other companies were not in business or specialised in parts for other brands.
Chrysler name was synonymous with Champion Sparkplugs.
A/C ( Albert Champion) ?
Autolite
Delco were the big hitters.
Test everything you use. New doesn't mean it works.
Just like tires.
Anyone who drove a car in the 60's and 70's knew that Firestone was the big guy, Good Years were second.
Now everyone acts like every car came with Goodyear Poly-Glas tires or T/A Radials.
Not the case.
Firestone dominated the racing scene from Indy , and they won every indycar race from 1910 until the Change of ownership in the 1980's.( which is where the Indy Low profile tire came from), NASCAR and stock class drag racing.
Do some research and only trust your own testing or personal research.
With parts selection. Most stuff has been Canada or Mexico made for decades.
Made in USA should really read, Made in North America. instead.
Engine mfg and assembly, mostly Mexico. Nobody complains much about Hellcat quality.
