I came across this and thought it could be handy to some of us.
I don't know how acurate it is so take it with a grain or 2 of salt.
http://www.gofastzone.com/techtips/sparkplugs/sparkplugs.htm
Jeff
I don't know how acurate it is so take it with a grain or 2 of salt.
http://www.gofastzone.com/techtips/sparkplugs/sparkplugs.htm
Jeff