I was shopping around for plugs for my 70' 292. I usually go to Napa cause they have an old school parts guy named Rob. Stuff I ask for isn't in the computer so the parts guys have to go to the "book". I love it! So the book calls for AC R45's. I get home gap em and now they don't fit in the spark plug hole. The R45's are 13/16". The ones I pulled out were AC R44's which are 5/8". Am I going nuts? About half a dozen parts houses give the same plug size.
