Spark plug issues

[Budgetmoparman]

I picked up new plugs for my 440 that I just rebuilt. The plugs I got are champion RJ12YC. The problem is that my heads have a small bump just below the spark plug hole. The motor is originally out of a 1976 motorhome. Is there a special smaller diameter plug that chrysler used? The threads are the same but the part of the plug just after the threads is too big. Hopefully someone will understand what I am talking about and point me in the right direction.

 

[Jim Lusk]

Yes, those head have extra cooling around the spark plug and take a smaller diameter plug. Somebody will know the part number.

 

[CudaJunction]

They are called peanut plugs. Just go by original application. They also fit small block chevys so very common.

 

[yellow rose]

They are called peanut plugs. Just go by original application. They also fit small block chevys so very common.

If it's a peanut plug it's not a J series. It would be a V series in Champion nomenclature.

 

[Budgetmoparman]

Thanks everyone for the replies. I was able to finally find a part number and the correct plug is a RV series not an RJ like yellow rose stated. Thanks for the help.

 

[jimjimjimmy]

RC12YC

 

[yellow rose]

RC12YC

You can't use the C series plug where you need a V series.

The C series is a 5/8 hex 3/4 reach plug. The N series is the same, only it has a 13/16 hex.
Both have 14 mm threads.

The J series is .375 reach, 13/16 hex with a gasket to seal it.
The V series is .460 reach, 5/8 hex and a tapered seat to seal.

You can't substitute a C for a J or a J for a V. You can use a C instead of an N.

Point is, the OP needed a .460 reach tapered seat plug. That's a V in a champion.

 

[jimjimjimmy]

You can't use the C series plug where you need a V series.

The C series is a 5/8 hex 3/4 reach plug. The N series is the same, only it has a 13/16 hex.
Both have 14 mm threads.

The J series is .375 reach, 13/16 hex with a gasket to seal it.
The V series is .460 reach, 5/8 hex and a tapered seat to seal.

You can't substitute a C for a J or a J for a V. You can use a C instead of an N.

Point is, the OP needed a .460 reach tapered seat plug. That's a V in a champion.

Sorry your 100% right I thought I seen 340 not 440 my apologies for any confusion caused .

 

[Ben Drinkin]

I'd like to buy a vowel...

 

[yellow rose]

I'd like to buy a vowel...

Yeah, I reread that post I wrote and got a headache.

Just proves I ain't no journalist.

 

[yellow rose]

Wait a minute...you been drinking. Can you even see straight?