Spark plug question

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Bam-Bam

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I have a 1967 Dodge Dart GT with a 273 4 bbl and 318 heads. I'm upgrading to Petronix Ignitor II electronic ignition and Flame-Thrower II coil.
My question is, what plugs do y'all recommend and what gap?
I am thinking Champion RN12YC set at .040.
 
Does Petronics have a gap recommendation? As far as the heat range, don't know what stock is but put them in and run it for 50 to 100 mi and see how far up the threads are burnt, should be 2 or 3 threads up.
 
Does Petronics have a gap recommendation? As far as the heat range, don't know what stock is but put them in and run it for 50 to 100 mi and see how far up the threads are burnt, should be 2 or 3 threads up.
Good question on the gap. I'll call them and ask
 
As long as they work Buddy and are gapped right, if you're happy I'm happy.
If you want to know what I use.. that would be NGK.

to each his own. Some of the fastest cars in the world have used one of all the major manufacturers I'm sure at some point.
 
I have a 1967 Dodge Dart GT with a 273 4 bbl and 318 heads. I'm upgrading to Petronix Ignitor II electronic ignition and Flame-Thrower II coil.
My question is, what plugs do y'all recommend and what gap?
I am thinking Champion RN12YC set at .040.

Due to the stupifying down of Google, I can not find an application chart for Champion anymore, that lists anything except their gold/ platinum plated specials. Anyhow, I would not gap them more than .040, and would probably just gap them at .035--original specs

I did not realize 273's took that hot a plug?
 
N10Y is what they called for back in the days, along with the 426 Hemi. I have a couple old Champion books. Now a days they just say everything needs the RN12Y. I have picked up a couple sets at swap meets over the years, along with all the other plugs the 340, 383, and 440 used. These are all NOS and made in the USA. I don't think they make them anymore. But do some searching.
 
Due to the stupifying down of Google, I can not find an application chart for Champion anymore, that lists anything except their gold/ platinum plated specials. Anyhow, I would not gap them more than .040, and would probably just gap them at .035--original specs

I did not realize 273's took that hot a plug?


There was a change in the heat ranges of almost everything in the mid 1990’s IIRC.

I used to have the Champion catalogs where I caught the change, and probably still do, although I’ve worn a few of them out and gave away a couple of them.

But yeah, I’m not sure if Champion corrected a catalog error, or changed the plugs to require a hotter plug for the same application but my weak memory tells me there was a major change in the fuel or something that warranted the hotter plugs.

The mid 90’s was a long way back!!!
 
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