NGK Set of 8 Ruthenium HX High Spark Plugs Gap 0.040" For Cadillac Chevy GMC V8

Work good with NGK ignition coils

I purchased these plugs online due to the availability & price-point. Local parts store quoted $52.00 per plug. Really? I've used Ruthenium plugs on a Turbo engine previously. [1.4L LUV] The upgrade was immensely significant. I've used Ruthenium plugs on a Non-Turbo engine. [3.5 L I5] The upgrade was not so noticeable. Here on the 5.3L V8, the upgrade made the Silverado have a smoother more refined feel. First the most noticeable aspect was engine starts. The engine starts almost instantly with almost barely cranking. The pedal got 'tightened up' slightly. I heard a SW re-tune is the answer to that. I don't really want to go down that road. So after that verbose dissertation, bottom line is just get these plugs. Plug #8 is NOT a good time! Also, agreed on plug gap. Plugs shipped with ~0.044, spec is 0.037->0.043. So, 0.040 is what is spec'ed out to be. Agreed, use caution on gapping due to the delicate electrode. JUST DO IT!

Added more power to vehicle. More responsiveness. Worth the purchase.

I've always had good experiences with NGK spark plugs. I would have given 5 starts but the plugs were factory gapped at .044" and my 2015 Silverado with 6.2L engine specifies 040" gap. The Amazon description says the gap is .040" and the NGK web site says the gap is .040", but the actual gap on all 8 plugs was .044". There is obviously a disconnect between the literature and the factory floor at NGK. A little time re-gapping the plugs and all is well. When re-gapping the ruthenium plugs you need to be careful not to damage the ultra fine ruthenium electrodes.

Easy install