I installed the rebuilt magneto and carbarator.  After 40 years of rest, My 1930 project ten is now a running cat.    Many, many things to fix in the upcoming winters.  

The cat has Edison x46 spark plugs. They appear to be in very good condition. I think I would like a spare set, or put in some modern plugs and save these original looking ones.  The are some very iffy looking x46 plugs on eBay for about $25 each.   Hhhmmm.  

I searched and found an old post on here saying to use Autolite 3077.  It seems this is no longer made?  There is a Autolite 3076 available, is that the correct size, but a colder plug? The electrode doesn’t look to stick out as far.  Another option I found is adapters to put modern,  smaller threaded, inexpensive spark plugs in.  But that would require some investigation to get the right length, probably non resistor, and heat range plugs.

the engine has some blow by, and not planning on heavy use or pulling, so I think staying with a hotter plug would be better for starting and not fouling from idling and worn cylinders/ lower compression???    

What is the ACMOC recommendation?

Hi Joe, I use the Autolite 3076 plugs on both my tens and on my fifteen with no problems. Rick