> Just checking the current Champion catalogue > > R= resistor > J= 14mm thread,3/8reach, 13/16 hex > 12= heat range > Y= standard projected core nose > C= copper core > > this is the correct plug for standard application 440 4bbl from > 67-74,the 440 2bbl took a hotter plug RJ14YC www.dodgecharger.com/forum/index.php?topic=13387.0;wap2
So it seems that some folks use J12YC, and some folks use RJ12YC.
A: NGK "R" or resistor spark plugs use a 5k ohm ceramic resistor in the spark plug to suppress ignition noise generated during sparking.
NGK strongly recommends using resistor spark plugs in any vehicle that uses on-board computer systems to monitor or control engine performance. This is because resistor spark plugs reduce electromagnetic interference with on-board electronics.
Ghost, this is quite exciting, thinking about what may be happening that you'd be in the need for some 440 spark plugs.