NGK R5724-8 Spark Plugs for 602, 603, 604's (Set of 8)
One of the most frequently asked questions we hear is "What spark plug do you recommend for a 602, 603, 604?"
This is the spark plug recommended by Crate Insider's Engine Builder Experts. Dyno testing and track testing have shown this plug to be the most durable as well as making the most power in the heat range.
Sold in sets of 8 (at a unit cost of $2.79 each).