I was wondering the same thing this afternoon
GAP .030"
Yes
no
RN11YC can also use RN12YC
Harley-Davidson uses .040" gap in their engines using this plug.
Rc12yc
your dum
A champion RC12YC spark plug is 14mm thread diameter. The torque for this size is 18-22 foot-pounds (25 to 30Neuton·meters)
depends how long you leave them in the freezer. The best I can remember, the 5R6A is the colder of the two.
0.035 inch gap using Champion RN12YC Spark Plugs
.035"