I had an 70 duster beater car which had a weak 318 engine and did burn some oil and I put new champions in it which fouled almost imediatly so everybody said put hotter heat range in so I special ordered some 16's and they fouled as fast as the 12's so then I tried autolites and it ran till I junked it, I think it had motercrafts before I changed to the champions and I didn't change the plugs because they were fouled it was just a tune up.This was in 1980 so maybe they have made a better product but it just left a bad taste for me, I have used autolites in other worn engines with great results.I don't claim to be a know -it-all but this is just some personal experiances.

Mitch