E3 Spark Plugs has a cast tron Chevy head/some Ford, non-resistor type spark plugs for 12.5-14.0 compression ratios. These spark plugs feature 14mm thread, a .46″ reach, a taper seat, and a standard tip reach.
E3’s patented edge-to-edge design increases the number of sharp edges and improves the spark discharge. The E3 DiamondFIRE design is open at the end, so the spark travels directly toward the air-fuel mixture which maximizes the burn. The result is a faster flame kernel, a more complete combustion, greater power, and higher fuel efficiency.
for more info: www.e3sparkplugs.com