how does a 318 engine run if timing is off ?
I agree but I'd suggest the RC14YC because of the 5/8 hex on the plug.
With iron heads you don't NEED the 5/8 hex but it still is a fair bit nicer than the N series with that big honking 13/16 hex.
EDIT: I was hoping Champion had the common sense God gave a gold fish and they'd drop ALL the N series plugs and just use the C series stuff. That would be a HUGE money savings to the company and they could put more focus on their racing plug line.
I doubt that will ever happen though.