To follow up, a few guys asked how to use one of these, here is what I do.

First, I use one indexer per engine. One side is for 1-3-5-7 the opposed is for 2-4-6-8

Mark, and install the plugs in your engine the way you want them, there are more than a few opinions as to where the plug electrode should go, I think pointing it across the exhaust valve should be OK for a start.
Now pull one plug out of the engine, install and tighten it into the indexer, try to use the same torque you previously used to put that same plug in the head, now find the line that you put on the spark plug, in alignment with that scribe a mark into the indexer, finally mark it with a number to match the cylinder you took the plug from.

Once you have an indexer for an engine, you no longer have to fight on the engine to get a plug to work, if you lay out the washers in order, thinnest to thickest, you will get a feel for how much each one pulls a electrode back.
It is very quick and easy, and you can do it any place you choose, just don't tell your wife I said it was OK to do at the kitchen table.......LOL


Rick