Whats the most used spark plug?

[hardcore302]

In all of automotive and OPE and other things that need plugs history, what's the most used spark plug model?

 

[mrsilv04]

J8 / J8C

 

[Chris142]

Used to be Autolite #64.

 

[fantastic]

J8 / J8C

Pretty sure my 1954 Lawn Boy specs that. I had trouble finding a replacement but did eventually. Did they use that model a lot?

 

[eljefino]

The Autolite 3923 "style"-- 14mm threads, 3/4" reach, crush gasket seat, 5/8" hex. Very, very common on anything with an aluminum head. Edit, looks like Chris' 64 is the same but with a 13/16 hex.

 

[Auto tech]

Champion for most ope