[ QUOTE ]
I have always used the Autolites,
what I'm trying to find out is do the R43 plugs have a specific application or is it a preference thing.
Thanks guys.
[/ QUOTE ]They are a colder plug used in the 69Z's and the L78 motors. I don't know of any other application they are used for. Maybe some earlier solid lifter motor corvettes.
I don't know if the 1970 High Perf. motors used them or not. Maybe a Yenko Deuce guy will chime in. I would say more of a racing plug.