Sami Said:
> I read somewhere that it may be advantageous to install spark plugs so
> that their open end faces the intake valve.  This can be achieved with the
> help of washers. This is to prevent the spark from occuring in the shadow 
> created by the electrode. Comments?
> 

This is called 'indexing' of the spark plugs and is a final tweeking 
in blue-printing an engine.  However, depending upon combustion swirl 
in the combustion chamber, the front of gas/air mixture may actually 
approach the plug from the rear.  I think overall, we're talking Nth 
fractions of a horsepower increase.  To me it borders on anal 
retentive.  Or, wait, is it obsessive/compulsive?

avoid the controversy and use a tri-electrode plug.....    and best of 
all, you don't have to admit you're A.R.  :)

-dan