440 U-Code Spark Plugs & Wires

[RT70]

Can you Mopar Experts give me some advice on what kind of Spark Plugs and Spark Plug Wires to use on my car. It is a 1970 Dodge Coronet R/T with a 440 U-Code, 727 Auto, and Dana-60 Rear. The car is still stock. The 1970 Dodge Service Manual for the Coronet recommends Champion J11Y or Mopar P-34P. Should I just get the J11Y off EBAY or is there a good after market Spark Plug? Also, any advice on a good set of Spark Plug Wires? I'm not a mechanic but can do minor maintenance. Thanks

 

[WileE]

If you're keeping the "original stock" look, then those plugs are the answer. You can get a set of date-coded (black) wires as well. If not... let the opinions begin...

 

[Jerry Hall]

I use Autolite 85's in my 70 440 4bbl Superbird with good results. Ofcourse I've never been able to get a Champion plug to last long in any of my Mopars. My engine is stock with the exception of a 440-6 cam.

 

[70 SUPERBIRD]

I use Autolite 85's in my 70 440 4bbl Superbird with good results. Ofcourse I've never been able to get a Champion plug to last long in any of my Mopars. My engine is stock with the exception of a 440-6 cam.

I use the same plugs. Never had any problems with them

 

[RT70]

If you're keeping the "original stock" look, then those plugs are the answer. You can get a set of date-coded (black) wires as well. If not... let the opinions begin...

Thanks

 

[RT70]

Thanks

I use Autolite 85's in my 70 440 4bbl Superbird with good results. Ofcourse I've never been able to get a Champion plug to last long in any of my Mopars. My engine is stock with the exception of a 440-6 cam.

Thanks

 

[RT70]

I use the same plugs. Never had any problems with them

thanks

 

[lewtot184]

J11y is the better plug but haven't been manufactured in decades. I use autolite 85's as a substitute. OEM wires would have been 7mm carbon core; farly high resistance. J11y plugs were non- resistor, 85's are resistor. OEM wire plus the 85 plug will have more resistance than original. It may be debatable as to the pro's and con's to this but i try to stay under the service manuals 9000 ohms resistance per cylinder.

 

[MWbirdLOVER70]

Contact Frank Badelson/Rodger Gibson Restorations for reproduction spark plug wires

 

[Don Frelier]

I guess I'm the exception.
I've seen several Autolite plugs bad right out the box.
I'd never buy/install them.

 

[dadsbee]

 

[Mopar Miki]

Don't be cheap about the spark plug wires - firecore spark plug wires, there is nothing better. None.

As for plugs many are stuck mentally in the 70's just like with operating temps, alignment specs and shocks. Today's fuel requires 195 F so get over it
From too many years of experience i find J11's are too cold. I run j14's in my current playtoy which gets run very hard and put away wet.

 

[RT70]

J11y is the better plug but haven't been manufactured in decades. I use autolite 85's as a substitute. OEM wires would have been 7mm carbon core; farly high resistance. J11y plugs were non- resistor, 85's are resistor. OEM wire plus the 85 plug will have more resistance than original. It may be debatable as to the pro's and con's to this but i try to stay under the service manuals 9000 ohms resistance per cylinder.

Thanks, another question: Is the Gap on the Spark Plug still .035" ?

 

[RT70]

I guess I'm the exception.
I've seen several Autolite plugs bad right out the box.
I'd never buy/install them.

I appreciate any information from you Mopar Experts !

 

[RT70]

Contact Frank Badelson/Rodger Gibson Restorations for reproduction spark plug wires

Thanks

 

[lewtot184]

Thanks, another question: Is the Gap on the Spark Plug still .035" ?

.035" is correct. i've used a lot of different brands of plugs thru the years. there will always be pro's and con's to any brand you buy. the "best" may only be as good as the application or tune-up skills. for general purpose the autolite 85 covers a lot of bases.

something else you might consider is making your own wires. it's not difficult at all. you will need the crimping tool and components but you'll end up with a perfect fit, and the ability to repair any wire if needed. i've been doing this for well over 50yrs. universal kits sorta fit, custom kits can be expensive but what if you booger or burn one and have to chase another wire?

 

[RemCharger]

Thanks, another question: Is the Gap on the Spark Plug still .035" ?

Yes, there's no extra anything to trying to run bigger. These are still cold war era chamber designs .

 

[lewtot184]

This is some of the stuff i do for making wires. Really the hot set up for header guys or just wanting a custom fit. A lot of possibilities with different types of wire and boots. Plus the added factor of being able to make your own repairs or changes.

 

[Geoff 2]

Unless you are circle track racing, have a power adder, or very high CR, there is no reason to use cold J11 plugs. After that era, spark plugs started using a copper centre electrode encased in a nickel/steel case that gave the plug a much wider heat range. Result was the centre electrode burned off the deposits from excess idling/low speed running that caused misfires/rough running. It also allowed hotter plugs to be used because the copper allowed for better heat dissipation than steel.
The correct plug is Champion 14 heat range, or 5 in NGK. Contrary to popular belief, you want the hottest plug that does not cause pre-ign....not the coldest plug.
Also a lot of nonsense written about the best plug wires & resistor plugs. In the test below a non-resistor plug came last & the leads with lowest resistance did NOT make the highest hp.