I was wanting to buy nos plugs for my 51 ford 239, but not sure of the old time number. I have heard that the new Champions are not as good.
Yes, H10C for copper. I have good luck with Champion, but have Autolite 216s in both my 8BAs. They work fine.
I have been running Autolight, but thought I would try the old original champions. Most of my problem has been running dual Holly 94s, with a fixed linkage. I have a progressive linkage but need to get longer base rods to hook it up. Plugs would carbon up frequently. I currently have the 2nd 94 disconnected.
Just get the H10C they work great and I use them in all of my flatties. The NOS ones will break the bank Lord knows I have about 5 sets just for my woodie and know from experience.