whilst that is true that both long body and short body plugs work in both onroad and offroad engines the long body plugs are better for off-road as they retain more heat and are determined as HOTTER plugs overall than the short body COLDER plugs for onroad.

So in fact there are ONROAD and OFF-ROAD plugs by the engine manufacturers. Novarossi being TGF or CT (short body) plugs for onroad and TGC or CTO plugs for off-road. OS being RP for onroad and P for off-road.

Both types of body plugs will work in both on and off road engines however choose the appropriate type for best performance.