NGK R5670-7 or -8

Not sure dollar for dollar the R NGK plugs can be beat.

They are 2.19 a plug at advance.


72 RR, Pump gas 440, 452s, 3800 lbs, Corked, ET Radials,. 11.33@117.72. Same car, bone stock 346s, 9.5 comp, baby solid. 12.24@110.