Take the cover off and clean the gasket apply some cement to it and put it back on again! I always aim the gap towards the intake valve and get better results that way - the idea is to ignite the coolest mixture first and the hotter areas where the exhost valves are will ignite good enough as the flame travels towards it. I end up with perfect idle and no skipping or misfires. The indexing washers should be thinner than a single plug thread pitch, I had a friend surface grind some washers down to various thicknesses to make a set.
Well that was informative. What's the difference between good plugs and bad ones?
I have heard that tons of times , that this plug works great and this one makes it run like poopy.
But..(theres always a but)
A plug from this manufacturer is mostly the same as from another.
Steel , ceramic , perhaps a copper electrode and thats about all thats in them.
The main difference from this brand to another is from their heat range ratings.
The heat range (which is usually indicated by the number) is how fast the heat will transfer from the plug to the head.
This influeces the heat level inside the combustion chamber.
Too cold and the engine will foul with unburnt fuel , drop power and eveentually missfire.
Too hot and preignition will result , and in extreme cases engine failure can result.
Many of the spark plug books conversion charts should only be used as a starting point.
Their actual listing of ?make-model = this plug? should likelwise also be a starting point.
Some manufactures guess quite well which plug is most likely suitable for your car , but some dont guess so well.
This is where one plug works better than another comes from.
If you had a so called BAD plug and read what the plug was saying (many new mechanics cant do this) by observing its colors , a change to a different heat range in the same brand will likely get it running sweet again.
MSD's and their multiple spark discharge box with their own high voltage coil is a logical choice.
Experimenting with spark plug gap would be quite easy to test with the Scangauge.
Could be something in that when combined with the MSD.