They developed that twin ground plug to combat misfires to save cat converters. I started seeing them in Tacoma pick-up trucks with the 3.4 engine. I am currently running Denso iridium plugs for a Toyota Tundra in my 10.9 compression 493 with Indy EZ heads and they run perfect all year long. I have considered using the twin ground plugs but it runs so well with the iridium plugs why change
Gus
Last edited by fourgearsavoy; 09/19/1710:09 PM.
64 Plymouth Savoy 493 Indy EZ's by Nick at Compu-Flow 5-Speed Richmond faceplate Liberty box Dana 60
