Originally Posted by martybechtel
autolite 605 or ar103 depending part store autolite web site had a pdf file that gave plug heat range but it is hard to find every I try to use .
Huh?
I'd try some of the NGK racing plugs, they work great.
Go by any Napa auto parts store tell then what you have and what the intended purpose is and they will hook you up.
They run about $2 a pop, which is not bad for a racing plug.
Goodluck, Cp