Originally Posted by Cab_Burge
My 518 C.I. low deck stroker motor with 15.0 to 1 compression liked Autolite #3934, it did NOT like any colder plugs whiney You can try those colder plugs but don't surprised if the 3934 or 3935 will work better twocents
Those Autolite racing plugs have a retracted gap and seem to last forever with our local pump E85 up scope


Thanks Cab, looks like those 3933's are definitely too cold then.. kinda like I suspected. Always appreciate your info.

1966 Satellie.. 12.55 @107.75. 906 heads. 3780 lbs.