Originally Posted By fast68plymouth
I like NGK’s.

At 12:1 you’re in the -7 or -8 heat range(higher is colder).


I run NGK #8's at 12.1.1 comp and they last a long time on the street testing carbs and general cruising BUT my motor is in a pretty optimum tune verified by track times, afr's, plug readings and a good street tune before I hit the track. Plug looks glazed over which is as stated HOT combustion chambers weather too much timing, lean, too hot of plug etc...........Good luck........... thumbs

72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....