Champion Spark plugs

[TOMRR]

I have J12YC Plugs Champions in my 440 and want to change. The part store have RJ12YC
Champions in stock. What is the difference and will they work ??

Thanks Tom C.

 

[ACME A12]

The "R" plugs are resistor plugs. These are intended to suppress RFI.

 

[Ernie]

Going to think I’m crazy but try AC Delco RapidFire plugs. Have used for years you will notice performance tick up. NAPA has
You’ll thank me later