David,
Okay, I have sorted my old plugs and looks like I can supply two sets of Titan plugs for the engines. The sets are not identical but if the engines are a few feet apart nobody will notice the difference. Sorry but I don't know whether the fat or thin porcelain is 100% correct. Maybe Ken does.

Where do I send the plugs?

You owe me for this one! or two!!

Jack is correct on the terminal nut was a big round ball that screw on to the CC plugs. Then the terminal wire just clipped on to the ball, Most Chev4 instruction manuals showed an illustration with the spark plug being grounded with a screw driver with these Connenicut connectors.
The CC used the thick type.
kenK

Hello Chip:

Do you want to bring them to Flint?

dave miner
330-492-7215

They are laid out ready to be boxed for shipment. No telling if they will ever surface again if put away for seven months.