Spark Plugs - what type?

[roadster68 <roadster68@shaw.ca>]

Thanks Pete for suggesting the 311.org site.  It suggests that the NGK  B-6E 
as the correct  plug.  A distributor here did not have that model but came 
up w/ the NGK  R6ES on a cross reference.  It has a fairly long threaded 
part.  I had heard that the "R" had something to do w/ resistance but I did 
not get the full story.  I only have the original radio in the car.  Can 
anyone tell if this one is okay?  Larry.