I remained silent till now on this as he got his answer. But I now wonder what his problem really is? All the 4.0L head swaps I've heard of run on the ragged edge of detonation issues. Unless he's flooding or burning oil I't think a hotter plug will only increase the likely hood of detonation and not really solve his problem??? -- Mark Price Morgantown, WV 1969 AMC Rambler, 4.0L, EFI, T-5 <~~!> Had he checked the valve stem seals ? =Bt= milnersXcoupe "The Heretic" _______________________________________________ Amc-list mailing list Amc-list@xxxxxxxxxxxx http://www.amc-list.com/mailman/listinfo/amc-list