Actually yesterday I received a return call from King Engineering who did the dyno tune of the engine in 2012. They gave me the plugs used at that time, NGK 2668. Most impressive!

So I have a set of those coming too now.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.