" From: "Swygert, Francis G MSgt 436 CES/CECM" <Francis.Swygert3@xxxxxxxxxxxx> " " " The strokers guys have found that running an 87-90 Renix spark plug in " the 91-06 HO engine (when stroked) will reduce pinging also. The " recommended plug for the Renix is shorter than the HO plug. Don't know " if that info will help or not. I think the longer reach plug is getting " hot and causing pre-detonation, the shorter one doesn't get as hot from " combustion. Just my opinion though! i think the renix works as much because it's a step colder than because of its reach. iirc folks have had a hard time finding other than stock plugs for the 4.0. if you're running lean you should definitely be able to run a colder plug. one of the standard reasons for a hotter one is to burn off the deposits created by short around-town-driving trips. on top of that, gas now probably doesn't leave the crud it used to. ________________________________________________________________________ Andrew Hay the genius nature internet rambler is to see what all have seen adh@xxxxxxxxxxxxxxxxx and think what none thought _______________________________________________ AMC-List mailing list AMC-List@xxxxxxxxxxxx http://www.amc-list.com/mailman/listinfo/amc-list or go to http://www.amc-list.com