Champion J11Y/Mopar P-34P spark plugs

[moparedtn]

Is the J11Y supposed to be the factory plug on big blocks (specifically, 440's)?
I went looking for some after I just installed a set of the only plugs the parts store had in stock recently (NGK). Needless to say, not impressed with those.
I then snagged up on an original set of Mopar 26422913 P-34P spark plugs still in the box for a pretty good price I think.

Were these the original plugs in our big blocks? Are they rare to find these days?
I paid $20 for the set of 8. How'd I do?

 

[moparnation74]

The original plugs for 440/426 were Champion J11Y.....

These are the correct plugs
https://www.ebay.com/itm/8-NOS-Cham...947857&hash=item3b0dc42e77:g:hUsAAOSwZs1Zhen0

The MOPAR version are champions but have the mopper name on them versus the champion name....

 

[Frank Mopar]

Mopar=Autolite. IMHO

 

[moparnation74]

Mopar=Autolite. IMHO

So your saying these are autolites.....

https://www.ebay.com/itm/NOS-MOPAR-...837548&hash=item4b43849617:g:6jwAAOSwR2RaAj5T
That is what he listed above as a part number??????

 

[Frank Mopar]

Let me rephrase.

Mopars like Autolites. Sorry for the confusion.

 

[moparnation74]

Let me rephrase.

Mopars like Autolites. Sorry for the confusion.

Ahhh...then I completely agree.....

 

[lewtot184]

the advantage to the j11y in an iron head is the length of the projected tip and heat range. the j11y and j13y were designed specifically for the big block iron head. the perfect spark plug.

 

[Daves69]

IMO, $20 for the J-11Y set is a good deal and they were the popular after market plug for BB Mopar as opposed to the Chrysler plug.

 

[lewtot184]

people bought the j11y because it was cheaper than going to mopar and buying the p34. they are the same plug.

 

[mopar 3 B]

Is the J11Y supposed to be the factory plug on big blocks (specifically, 440's)?
I went looking for some after I just installed a set of the only plugs the parts store had in stock recently (NGK). Needless to say, not impressed with those.
I then snagged up on an original set of Mopar 26422913 P-34P spark plugs still in the box for a pretty good price I think.

Were these the original plugs in our big blocks? Are they rare to find these days?
I paid $20 for the set of 8. How'd I do?

What was unimpressive about the NGK's?

 

[moparedtn]

Well thanks y'all. Yeah, I'm kind of tickled to get these at that price. They didn't show up at first on eBay using normal search but I learned a long time ago that eBay's search engine has some odd characteristics to it and that items get "lost" on normal searches.
I did a little backdoor digging through a portal and there they were, languishing with no bids and a day left.
Watched it, snagged it.

Now I'm rethinking actually installing them.
Any collector/artifact value to these? Kinda cool with the Mopar script and box and all.

 

[moparedtn]

What was unimpressive about the NGK's?

These are just the garden variety "v power" ones, but they're certainly a colder plug than I need. You can just feel it in the idle quality and tip-in on the throttle; just a little sluggish to respond, especially until the engine is fully warmed up.
My butt-meter tells me they need to be a warmer range.

 

[mopar 3 B]

These are just the garden variety "v power" ones, but they're certainly a colder plug than I need. You can just feel it in the idle quality and tip-in on the throttle; just a little sluggish to respond, especially until the engine is fully warmed up.
My butt-meter tells me they need to be a warmer range.

That can happen with any brand of plug. I found even the original factor Champion plug undesirable in a built BB. Reliability was the key reason for ditching Champions in the 1980s. Simply got tired of plug failure after a few thousand miles.

 

[moparedtn]

That can happen with any brand of plug. I found even the original factor Champion plug undesirable in a built BB. Reliability was the key reason for ditching Champions in the 1980s. Simply got tired of plug failure after a few thousand miles.

I always ran Autolites in my 440 cars back in the 80's. You're correct, the Champions of those days had gone downhill in quality.
My current engine certainly isn't "built", just a rebuild of a stock one with a bit of porting and a 484 purpleshaft cam, headers, etc.
Problem is, where I live the parts stores don't really carry a lot for older rides; everything is ordered, which of course I can do instead.

Regardless, here I have some original Mopar issue Champions (notice these were made before the part number was superseded), so I'd guess they
are the "good" old OE Champions.

 

[Mopars & Missiles]

Is the J11Y supposed to be the factory plug on big blocks (specifically, 440's)?

I then snagged up on an original set of Mopar 26422913 P-34P spark plugs still in the box for a pretty good price I think.

Since I'm not sure what year your car is, this info is for 1969 models only. Other years are similar, but check your FSM and/or Operators Manual for specifics, its in there.

Champion J11Y's or Mopar P-34P's are the factory recommended plugs for 1969 model 383 HP's & 440 HP's.

For a 1969 model 426 Hemi, the recommended plug is a N10Y Champion.

 

[mopar 3 B]

Since I'm not sure what year your car is, this info is for 1969 models only. Other years are similar, but check your FSM and/or Operators Manual for specifics, its in there.

Champion J11Y's or Mopar P-34P's are the factory recommended plugs for 1969 model 383's & 440's.

For a 1969 model 426 Hemi, the recommended plug is a N10Y Champion.

Note: recommended not absolute. When you find something that works stick with it. The next person may not like your choice at all. Its just the way it is in the car world.

 

[moparnation74]

If I was not doing an original OE build......I would choose the "Best" plug for the build application......This is a trial and error process sometimes

To moparedtn, That is a good price btw for those plugs......Good score....

 

[lewtot184]

Well thanks y'all. Yeah, I'm kind of tickled to get these at that price. They didn't show up at first on eBay using normal search but I learned a long time ago that eBay's search engine has some odd characteristics to it and that items get "lost" on normal searches.
I did a little backdoor digging through a portal and there they were, languishing with no bids and a day left.
Watched it, snagged it.

View attachment 607662
View attachment 607663 View attachment 607664

Now I'm rethinking actually installing them.
Any collector/artifact value to these? Kinda cool with the Mopar script and box and all.

what's interesting is to compare the projected tip length on the j11y to a j10y, j12y, autolite 85, 74, 75 or any other 14mm 3/8" reach plug. you'll notice the j11y tip is longer and non-resistor. big block mopars have a very crummy combustion chamber. the plug is at the extreme end of the combustion chamber and then combined with a large bore. all the modern 14mm 3/8" reach plugs are designed for the small chevy chamber. the difference isn't great but every little bit helps. somewhere in the '70's a OJ11Y was made; a resistor version of the old j11y. all modern plugs have about 5000 ohms of resistance. this may or may not be a problem, depending on other factors, but should factored in. I don't get lost in who's name is on the plug anymore. I do physically compare heat ranges and tip lengths and keep an eye how they burn.

 

[moparedtn]

Since I'm not sure what year your car is, this info is for 1969 models only. Other years are similar, but check your FSM and/or Operators Manual for specifics, its in there.
Champion J11Y's or Mopar P-34P's are the factory recommended plugs for 1969 model 383's & 440's.
For a 1969 model 426 Hemi, the recommended plug is a N10Y Champion.

1968 440. FSM says J11Y or P-34P for 383 and 440. Interestingly, it also says if those aren't available, then the J10Y is a suitable replacement.

To moparedtn, That is a good price btw for those plugs......Good score....

Thanks!

Now, do I use them or hang onto them?

 

[mopar 3 B]

Check the plugs in it now and proceed from there. Let the plug till you which way to go.