Yea, it's a little different. It's the original engine in a '66 Coronet 440, barn find, that sat since 1981. I picked it up last year and with my boys help, am in the process of putting it back on the road. I wanted to keep it as original as I could. Hate spending the money to stay 361, but everybody and their brother has a 440. I figured if I was going to go 361, I would at least stroke it a little. I am getting ready to order pistons, probably from someone on Moparts. That is why I was asking about the plugs, so I can do a proper CC on the heads before I order. I plan on running the Pertronix with no ballast, as I think they recommend that. I agree with you on NGK. They do look quality. I went on Mancinis to get the number. Thanks to all who responded. I love this place. Pat