B/RB Plugs

[Stumper]

I’m sure this has been beat to death, but looking for opinions on the best plug to use in a stock built 361 / 4bbl with 727. I am reading that a J11 was the OEM but most references seem to indicate a 12 heat range these days. Since it’s not likely I’ll find J11s at the local parts stores is a 12yc a good plug to use? Is a 14yc too hot?. Also am I correct that a RJ is shorter reach than an RC - and is the RC too long?

 

[WileE]

you can get J11y... they're around and readily available... places like ebay, etc.

 

[toolmanmike]

I’m sure this has been beat to death, but looking for opinions on the best plug to use in a stock built 361 / 4bbl with 727. I am reading that a J11 was the OEM but most references seem to indicate a 12 heat range these days. Since it’s not likely I’ll find J11s at the local parts stores is a 12yc a good plug to use? Is a 14yc too hot?. Also am I correct that a RJ is shorter reach than an RC - and is the RC too long?

I would use a 12 or a 13. The gas isn't as volatile as it once was. I ran into that with my 273. 10's we stock, Anyolite's conversion took me to 9's which were way too cold. (It idled like crap.) 2 barrel engines ran 14's. I settled on 12's and they worked perfect. In fact, they are still in there and doing well. (probably 12,000 miles)

 

[mopar 3 B]

Champion also changes the heat range in their plugs over 30 years ago. The J11Y may not even be what you need. Like in you may have to experiment a little to find the heat range it needs.

 

[MoparLeo]

https://www.championautoparts.com/f...]=Plymouth&model[value]=364&model[label]=Fury
https://www.sparkplug-crossreference.com/
https://www.briskusa.com/spark_plug_cross_reference_heat_range_chart

 

[mopar 3 B]

https://www.championautoparts.com/find-my-part/Find-My-Part-Results.html?type[value]=2&type[label]=Light Duty&year[value]=1962&year[label]=1962&make[value]=43&make[label]=Plymouth&model[value]=364&model[label]=Fury
https://www.sparkplug-crossreference.com/
https://www.briskusa.com/spark_plug_cross_reference_heat_range_chart

Those are fine for a stock engine. Anything else will take some experimenting. Even with the stock engine different localities provide different fuels. So starting with the recommended and experimenting may still be required.

 

[RJRENTON]

IMO.....
The "CORRECT" plugs are determined by several factors: REACH, CAM, COMPRESSION RATIOS, IGNITION ADVANCE CHARACTERISTICS and probably, intended use.
The Champion J-11Y or Mopar P34P plugs are available on the internet and eBay. I've purchased a large quantity of P34P Mopar plugs at a reasonable price. The Champion RJ-12YC replacement, for the J-11Y is a broad based heat range and will perform well. Likewise Autolite AP-85 is a platinum electrode design, very reasonably priced and readily available, and work well. AC R43S / R44S will also give satisfactory service.
For my application, 1970 Plymouth GTX RS23V0A******, with a cam, high compression ratio and origional Prestolite dual point distributor, and Dana 60 4,10 gears and 4 speed transmission, I use either Champion UJ-11G (paladium alloy center electrodes non projected nose plug) or Champion HO-8A platinum center electrode moderate heat range, NON projected nose, both being 3/8" reach design. The UJ-11G plug is a moderate heat range designed for 2 cycle engines. The HO-8A was designed for Homelite 2 cycle racing go kart engines burning methanol and nitromethane and castor oil fuel mixture running at 10k RPMs. Why did I select these plugs??......they were available and inexpensive.....and most importantly.....they work extremely well and offer a broad based heat range....the small diameter center electrode heats quickly to prevent fouling yet prevents over heating (due to the alloy which conducts heat transfer due to incoming charge cooling effect better). Will they work for your application?......probably.....how available are they?....difficult but not impossible to find....moderately expensive ($5 - $6 each). Both AC and Autolite will work well also.....but....you've got to try a brand name (what ever that brand is) and heat range to establish a base line starting point to be able to make comparisons either up (hotter) or down (colder). What works for me may/may not work for you. I'm sure others will have their own preferences and opinions. Points to ponder...
BOB RENTON

 

[Stumper]

Guy at Advance Auto said a RJ14YC is what they show..
I plan on using ethanol free 90 octane so I’m wondering if I’d be better off with 14 range instead of a 12? Again this is a stock motor.

 

[MoparLeo]

All you have to do is click on the links I posted. Tells you the factory installed plugs and other links explain heat ranges and plug nomenclature if you want to know about reach etc...
OP asked for info on a stock engine.

 

[beanhead]

Guy at Advance Auto said a RJ14YC is what they show..
I plan on using ethanol free 90 octane so I’m wondering if I’d be better off with 14 range instead of a 12? Again this is a stock motor.

If you're unsure which heat range to use, you can mix and match them. Put 2 of each range on each head. After getting some miles on, pull them and compare the heat coloration on the threads. Won't hurt a thing to temporarily run a step in either direction as long as your two choices aren't way out in left field to begin with.

 

[RemCharger]

Ngk xr5. Sure they're the best, but at least they're cheap.

(Ever wonder why Champs used to come in boxes of 10?.....)

 

[Ironbuilt]

I second the NGK XR5. I use the 3332.

 

[JG71B]

Guy at Advance Auto said a RJ14YC is what they show..
I plan on using ethanol free 90 octane so I’m wondering if I’d be better off with 14 range instead of a 12? Again this is a stock motor.

I'm using that same fuel from Chardon Oil locally. I have a 50k mile original 1978 400 4bbl motor. All stock but a performer aluminum intake and headers. I ran the NGK XR5, the Champion 14's and 12's. Timing is initial about 15-17 btdc and 36 total. The Champion 12's seem perfect after trying all 3. Nice tan color, no detonation or fouling as of yet. Seemed the 14's showed signs of slight detonating so I went to 12's. Stock ignition accept for an Accell Super Stock chrome coil and orange ECU. You need to drive a good 10-20 miles normal and some highway driving to get a good read IMO

 

[Stumper]

I'm using that same fuel from Chardon Oil locally. I have a 50k mile original 1978 400 4bbl motor. All stock but a performer aluminum intake and headers. I ran the NGK XR5, the Champion 14's and 12's. Timing is initial about 15-17 btdc and 36 total. The Champion 12's seem perfect after trying all 3. Nice tan color, no detonation or fouling as of yet. Seemed the 14's showed signs of slight detonating so I went to 12's. Stock ignition accept for an Accell Super Stock chrome coil and orange ECU. You need to drive a good 10-20 miles normal and some highway driving to get a good read IMO

 

[Stumper]

Thanks for the reply post. I think I will try a set of 12s first. I’ve always remembered 12s as the go to plug for stock engines and was surprised that the 14s were coming up as the recommended plug. Then again maybe the 14s are better for the crappy gas we have these days…

 

[RJRENTON]

Thanks for the reply post. I think I will try a set of 12s first. I’ve always remembered 12s as the go to plug for stock engines and was surprised that the 14s were coming up as the recommended plug. Then again maybe the 14s are better for the crappy gas we have these days…

USUALLY....with the later engines, especially the ones using heavy EGR (Exhaust Gas Recirculation), prior to the use of fuel injection, needed a hotter plug, like the Champion RJ-14YC in lieu of the standard RJ-12YC, because the EGR lowers the combustion chamber temps to reduce NOx formation (Oxides of Nitrogen) and to reduce any fouling possibilities. Actually, ethanol blended gasoline has less heating value than just gasoline and burns cleaner even though you have to add more, a richer mixture, to achieve better combustion.
BOB RENTON

 

[Stumper]

No EGR on mine, in fact no PCV either. It still has the draft tube.

 

[mopar 3 B]

No EGR on mine, in fact no PCV either. It still has the draft tube.

Just what year is this engine?

 

[Stumper]

Just what year is this engine?

Haven’t looked it up yet 2205712-8

 

[RJRENTON]

No EGR on mine, in fact no PCV either. It still has the draft tube.

What is the MAKE, MODEL, YEAR OF THE VEHICLE AND ENGINE SIZE. OR THE VIN OR A PIX OF THE FENDER TAG....will go along way to supply you information....
BOB RENTON