Thread: spark plugs

so i got autolite 606's and autolite 104's and i am planning on dropping my pulley in the kind-of near future and i was wondering if i should stick with the 606's or go ahead and use the 104's now? and im guessing a .053 gap on the 104's or a .055 gap on the 606's. any recommendations? thanks

edit: also would a smaller gap be better? in a post here i saw that a .050 gap for copper plugs is recommended. any truth to that?