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#57: 04-03-2013, 01:10 AM
spark plug indexing
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Originally Posted by Sludgeroo View Post
For indexing (great idea by the way), I think you would actually put the black line opposite the side where the j strap meets the plug. You would put it on the gap side, that way when the black line is at 12 o clock (perpendicular to the ground) the gap will face comb chamber.
I guess it depends on where you want the flame front facing. I'm not very familiar with the geometry of the Subaru engine yet.

Here are some examples:

Those pics have lines on plugs opposite of each other so depends of engine design.

Here is a Google search for spark plug indexing:

I learned of the concept from a Big Daddy Don Garlits interview on tv
about 20 years ago.