Spark plugs
Ok, out of curiosity I looked up that plug. I'm pretty sure (99% sure) that there was never a cylinder head made for any V8 Chrylser that used a 10mm 3/4 reach plug.
So I'm doubting that plug number. The heat range I don't doubt, but the C plug in an NGK is a 10mm 3/4 reach. If that is the plug used I'm not sure how it stays in the plug hole.
Now I am curious.
BTW, IMO that plug is a range, maybe two too cold. But I'd rather see some pictures of the plugs before I owned that.