Trailing/Leading Spark Plugs?
 

I have just found a total of eight spark plugs for the 13B, and they're all mixed up. Does anyone know how to tell the difference between the trailing (upper) and leading (lower) spark plugs?

THANKS!

8?? ...well, the Trailing plugs have a "T" marking on them, and the leading have a "L" on them...im not sure if this helps or not.

the will have an L and T on them somewhere.

otherwise the trailing will have a 9 in the part number. and the leading will be the same # except it'll have a 7 instead.

The NGK 9- trailing has 2-blue bands at ends, 7-Leading is all white.

Wow! This all helps very much! Thanks!