I have a set of Champion plugs with the number N-R 176 stamped on them and another set with N-R 167stamped. The numbers are stamped on the metal body of the plug. They have a dual retracted electrode, are 14mm, and have a 3/4" reach. I use them in a turbo Ford Twin Cam race engine that runs on methanol. It's a 70's engine so I ***ume the plugs are that vintage as well. I would like to know what might be an acceptable subs***ute on the market today. I have not been able to locate any of the plugs I mentioned above and fear that someday I may need to replace what I have. Any help appreciated. Thanks, Bruce
We've had very good luck with NGK, we sprayed lots of nitrous so it was a very turbulent atmosphere. Have as look at NGK R5671A-8 or -9 for even colder. We closed the gap to .025ish with a good MSD ignition. It'd miss with .035gap due to the turbulance in the combustion chamber. Under $20 a set. We were using AutoLite AR 3933/32? but thye took too long to get a good read. At first I used the NGK to check tuneup and would switch to Autolite because we trusted them. After a while I just starting leaving the NGK in. You'll be able to read them after a single p***.
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