CarlsonMotorsports
Site Supporter
I don't know about the validity of .3; Jimbo did the testing, not me, but I can guarantee you that you want to use (and MUST use) the Autolite 3910X plug after March 31st -- it is NOT a choice with the Briggs rules.
From testing we did 12-15 years ago on the alcohol animal engines, the 3910X plug did help over shorter reach plugs.
We were cutting the shoulder on the iridium Denso plugs .080" in a lathe before that, and I can guarantee you that no one bought those plugs from us for $5! LOL
From testing we did 12-15 years ago on the alcohol animal engines, the 3910X plug did help over shorter reach plugs.
We were cutting the shoulder on the iridium Denso plugs .080" in a lathe before that, and I can guarantee you that no one bought those plugs from us for $5! LOL