There is a special spark plug for this application...
https://www.aopa.org/news-and-media/...powerplant-(3)
This whole heat-range equation can be summed up by looking at a special spark plug created for the Lycoming O-235 L2C engine developed for the Cessna 152. When first introduced, this engine kept technicians very busy cleaning spark plugs. The engine had the unprecedented characteristic of extracting what seemed like all of the tet-raethyl lead in the fuel before depositing it on the firing end of the recommended RHM 40E spark plug. Champion quickly developed the RHM 37BY, a colder plug with an unusual-appearing extended tip. This plug was designed specifically to deal with the lead-fouling problem in that particular engine. It has done that job so well that it's now approved for installation in many low-compression engines that need help preventing lead fouling.