See all kinds of cross reference charts, they are similar but just little difference. Trying to find local source after accidentally cracking one and realized I had to order spares, no parts store had one in stock.

I called Champion to see if they would help but was told they are discontinue the racing line of plugs, Anyone else heard this?

Does anyone had any real dimensions?
I did some rough measuring the depth into the threads and height of electrode on few sets of different plugs I had around here.

I started this with a chart from Autolite to convert. I dug thru master catalogs looking for similar plugs and added them just for comparison