E3.90R-9 Racing Spark Plug

E3.90R-9 is a 14mm, 0.750” reach plug with a 5/8” hex and a gasket seat. It is built to have a cold heat range, non-resistor, and is used a variety of racing applications. E3 "R-series" racing plugs are fitted with a nickel alloy ground electrode. This allows for excellent heat transfer and an adjustable gap for high compression engines. 

CROSS-REFERENCE
        Autolite AR3933
        NGK 5238, R5671A-9