I haven't bought and used a set of those heads yet on my bracket E85 S/P car yet but if they take a 3/4 inch reach plugs like SB and 426 hemi use try a Autolite #3933 or the next hotter 3934.
I have ran these plugs in both of my bracket motors with aluminum Eddy Victor M.W. on the old motor and with the Indy 440-1 at 15.0 to 1 compression on the new 400 block stroker motor shruggy
IHTHs scope

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)