Mopar NOS Spark Plugs

[mopar73dge]

Does anyone know the difference between the original Mopar Champion plugs P34 and P65 plugs ? will a P34 run in a small block?.

Who are the expert's out there?

thanks

 

[RJRENTON]

Mopar 73...
The Mopar P34P (Champion J11Y) are 3/8" reach or thread length, projected core nose insulator and are of cold heat range. All LA block engines use a 3/4" reach plug of a medium hot heat range....Champion N12Y or N11Y. Only the old polyhead 318s used a 3/8' reach plug...Champion J12Y or J13Y. DO NOT INSTALL THE 3/4" REACH PLUGS IN THE B or RB engines EXCEPT THE HEMI WHICH USES THE 3/4" REACH PLUGS.....N10Y OR N12Y WILL FIT AND FUNCTION CORRECTLY. Hope this helps with your quest. I'm sure others will have differing opinions as to which plug is best. Heat range and brand notwithstanding you MUST get the reach length correct....which is determined by the cylinder head configuration.
Bob Renton

 

[mopar73dge]

Thanks for the info much appreciated

 

[mopar73dge]

Here are the plugs I have to use, would these be correct?

 

[RJRENTON]

Please unwrap one....and measure the thread length and firing end to get a better look at the plug. I think it's a 3/4" reach plug but MAY be a taper seat plug used in the later generation slant 6 engine without the spark plug tubes. A pix would be nice.
Bob Renton

 

[lewtot184]

34p is a big block plug.

 

[SublimeSixpack]

I think the Mopar P87P plug will work in your small block, but do you really want to open them up? How old are they? Might be nice to hang onto those just as they are, (NOS).

Correction: P67P

 

[mopar73dge]

I think the p34 information was a mistake on my part, the plugs as shown in the photo are a p67 plug with 3/4 inch reach. I found a chart with all the plug types from an E bay seller's item, he had the nos plug box with a chart on the back of it. So the 67 plug is for a 318 for 1976, or a 1973 340. part numbers vary of course. I will use the NOS p67. which I believe will work just fine in my 318 with a 340 spec cam. Thank you for all your help Bob.

 

[mopar73dge]

I will keep the NOS box for display and live like today is my last day, I will be installing the plugs in the engine, I want to have the best I can get.

 

[mopar73dge]

Plugs installed and perform very well! (P-67-P) that's it, I am done. Those will stay in there for the next 15000 miles, which will equal to about 14 years of driving this car during the nice North East months