most plugs will come correct or close enough to not worry about at least ngk. The denso plugs im not sure i havent used those much i know i saw a couple failures with them.
run somewheres around .030-.032 on bigger builds that run at a higher rpm you can close them up some and it will help with blow out also alcohol and some other fuels i have tested will like different gaps but on normal stuff with normal fuels those numbers should do you well i think denso follows the same gap as ngk but im not 100% positive
run somewheres around .030-.032 on bigger builds that run at a higher rpm you can close them up some and it will help with blow out also alcohol and some other fuels i have tested will like different gaps but on normal stuff with normal fuels those numbers should do you well i think denso follows the same gap as ngk but im not 100% positive