Snip Yes, but trying to find the "13" plug is proving to be a a challenge. It seems that many spark plug lines, Champion included, are moving towards part numbers that describe nothing about the plug itself (physical size, element material, heat range, etc). Maybe that's old news, but the point is I'm having a hell of a time trying to find a "hot" plug. I do have fouling problems, particularly on 3 and 4, perhaps partly caused by the mis-jetted weber 38/38, but that's a whole 'nother post... Snip While Champion no longer produces user friendly catalogs like they used too, the next heat range up from RC12LYC Catalog number 412 is a RFN14LY catalog number 82. However I think the better question already asked, is what is the problem? If fouling from a carburetor setting (would have to be really bad) has been corrected with a carburetor setting you should not need a hotter plug. If oil burning is the problem, a hotter plug is a band aid. Hotter plugs lead towards detonation and pinging. A Hotter plug yet leads to more detonation and pinging. I personally have never needed a hotter plug! But colder ones have bought measurable benefits. I think some one made the statement that most 4.0 problems are related to pinging. Most people I know or have heard that complain about pinging try to run them on 87 octane gasoline. Well duh! Spend an extra dime and put high test in it. A lot of pinging stops that way. I run 3 heat ranges colder on all of my AMC engines. Spark plugs last almost forever! My engines don't ping! And the latest timing is set at any time is factory stock. But for what it is worth, an 82 is hotter than a 412 in champion. John. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.amc-list.com/pipermail/amc-list/attachments/20070322/f3174670/attachment.htm _______________________________________________ Amc-list mailing list Amc-list@xxxxxxxxxxxx http://www.amc-list.com/mailman/listinfo/amc-list