Hard to see the plug threads to count the number of threads the color change occurs at. From what I've read, it looks like its happening at the 3rd thread down from the tip, which should be ideal heat range wise.
As far as tuning for A/F mixture, buy and install a wide band and take the guess work out of it. Best tuning tool ever invented in my book.
Last edited by jbc426; 07/06/18 01:34 PM.
1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's
1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)
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