Then the J12Y variant would be a good option. Just as a historical reference, the J12Y plug was used in 283 chevys, Mopar motors, Harley Motorcycles, all kinds of engines. The J12Y plugs are the original variant (along with the R designation for resistor to keep radio noise down). the J12YC (C for copper) are the newer and current variant. Any of them will work.
The J14Y are the same plug but hotter (not in terms of spark but in terms of thermal temperature). Also fine to use if you cant find the J12Ys locally.
You might see J11Y and J10Y on ebay or facebook market place. These were colder plugs, generally for commercial use, taxis, trucks, but no longer available. Also used by racers for race motors. I scrounge them up when I come across them as I have used them for racing.
