Curious to see what people have as sparkplugs in their redblocks and also preferred heat ranges!!!

Goldenblock

 

I nearly always used Bosch Super 7900, aka WR7DC, or NGK BPR6ES

these engines aren't very fussy., but 'platinum' or 'iridium' plugs are a waste on them, they are happier with old school copper plugs.

 

Just as Pierce said, the copper plugs work just fine on these engines. I, however use the Bosch WR6DC in my car now. It is a plug 1 step cooler than the aforementioned stock WR7DC. It helps to prevent the knocking I sometimes get in hot weather when the A/C is on. I changed to that range in the hope that it (and some other things) would help my NOx emissions in trying to stay good with the CA. Smog checks. It has worked.

 

plug temperature ratings are often misundertstood.

a 'hotter plug' is able to dissipate more heat so it runs cooler, this is suitable for a hotter engine. a 'cooler' plug has less heat dissipation capability, so it runs hotter, better for a cooler engine as it keeps deposits from accumulating.

many car engines spec a hotter plug in Europe than they do in the US, as highway speeds are higher, so the engines are running higher RPMs. Americans seem to like their engines running barely above idle.