What spark plug should i be putting in my 440? I live in Indiana, if that matters as far as elevation.
RJ12YC Champions is probably the most often suggested plugs. I have had good luck with NGK plugs but Chryco and others have not. I just put the Champions in my son's car that we dropped a 440 into...
On the dyno years back the best power was made with Campion or Autolite plugs , the more expensive the plug the more power lost .
I have never had good luck with NGK ,they foul too easily & quit working .
Thanks, Champions
I forgot to ask about gaps. Where should the spark plug gaps be set?
Years ago I always ran Autolite in my 69 440 GTX, just a bracket car so no dyno but seemed to run better. That said I ran/run Champions in my 70 440 Challenger and have no complaints.
As far as gap, the called for is .035. If you have an MSD or other "high-spark" system you can go with .040.
Thanks for the help
Anyone have any experience with the E3 plugs???
Quote from: chargerdon on July 25, 2022, 06:02:28 AM
Anyone have any experience with the E3 plugs???
I have a small business servicing and repairing small engine equipment. Those E3 plugs make me a lot of money in service calls. Customers install them thinking they cost more they must be better. Non starting or rough running, first think I do is look at the plug, if it's an E3 it's usually easy money for me.
I have not bought plugs in a very long time. I was looking up info and came across this thread so I then went to buy spark plugs for basically stock 69 and 70 440's. (factory is J11Y). I was just going to keep it simple and get the RJ12YC mentioned in an above post. The guy at the auto parts store starts telling me about the resistor in them and I need to find ones without which he doesn't sell. I know what the resistor is for (stops RF for modern cars), but is this something I need to worry about impacting driveability/performance on my stock 69 and 70 Mopars? (note that some still have points and others the Chromebox electronic conversion)
My experience with NGK's has been the same as Chryco mentioned, they foul very easily and never clean themselves up. I switched to Champion RJ12YC in my stroked 440 with an MSD 6AL box and the engine runs much better especially in the higher RPM range. I have the gap set at .45 but stock spec as mentioned earlier without an MSD would be .35. I wouldn't concern yourself about resistor vs no resistor, the RJ's work well in these motors.
Quote from: 73Dodge on December 09, 2022, 03:10:26 AM
My experience with NGK's has been the same as Chryco mentioned, they foul very easily and never clean themselves up. I switched to Champion RJ12YC in my stroked 440 with an MSD 6AL box and the engine runs much better especially in the higher RPM range. I have the gap set at .45 but stock spec as mentioned earlier without an MSD would be .35. I wouldn't concern yourself about resistor vs no resistor, the RJ's work well in these motors.
Thanks, I am more concerned with drive-ability at this stage in my life anyway. Less fouling means less headaches. I also have one lone 340 car. A stock 70 AAR cuda 6 pack. (factory is N9Y). Could you recommend which plugs I should get for that? (currently this car has points, but at some point I plan to switch to the chrome electronic box)
70Challenger440, I just asked that same question about my 70 340 T/A ( on another forum ) and havn't gotten any replies. So lets see if we get any feedback from the T/A -AAR guys. Thanks , Kevin
This is a timely post. Now I know what plugs to buy for our 383 / 478 stroker. Champion RJ12YC it is. and, 0.035 gap.
Thank you.
The Champion RJ12YC and if you need one or two steps colder, go RJ11YC or RJ9YC.