I was wondering if the AP wasp .061 glow heads are interchangeable with the Big mig Norvel plugs. I believe someone had told me that the threads were not interchangeable.The plug itself appears to be the same shape as the Norvels. I have a plug on a Norvel AME .049 that doesn't seem to do so well since the time it was purchased. I read later that some of the Norvel plugs were possibly 3 volt plugs. I've never tried more voltage but the Galbreath head and Nelson combination has been working. I'm curious to know if anyone else has tried the AP plug.

Norvel, VA, Stehls and AP all use the same head thread as the C*x.  I have found that the Galbreath/Nelson plug combination works better than anything else, usually to the tune of 1000 rpm improvement.