One of the most frequently asked questions we hear is, "what kind of spark plugs do you recommend for a 602, 603 or 604?" Our engine builder experts agree and have told us:
"The plugs we've had the most success with, meaning they last a long time, are the NGK R5724-8's. We've dyno tested pretty much every plug out there, and have proven that any plug in the right heat range makes the same power. However, watch out for the "novelty" plugs on the market (I.E. Platinum this, or Sure fire that, or Split fire BS). They actually show a power loss on the dyno."
We now carry the NGK's in our store at the following link:
Pick up a set and try them for yourself.