on 9/5/03 4:57 PM, Trooper at [EMAIL PROTECTED] wrote: > I just finished a complete rebuild on a 69 396 and wanted some input on > what number of AC plug to use on the motor. The heads are 69 castings > w/o the tapered plug seat. They are closed chamber heads. I am also > running HEI ignition. My big question is do I use AC R43XLS (long > threads), this is what the book says to use but man they look long, or > AC R43S (short threads) What are you BB guys running in your motors? > > Trooper > > _______________________________________________ > Chevelle-list mailing list > [EMAIL PROTECTED] > http://chevelles.net/mailman/listinfo/chevelle-list_chevelles.net Trooper,
Didn't remember seeing any responses to this one, so I'll give it a shot... I remember installing the XLS plugs back when the cars were new, and if your heads are the standard "flat washer" type (not the tapered seat style) these are the correct [plugs for your '69. If your heads are the original '69 castings, they'll have the standard "flat" plug seats. The tapered seat (or "peanut") plugs were introduced during the '70 model run... some of the earliest '70 engines actually used the flat washer style, others used the tapered seats... even though they both used the same 290 or 291 castings. Ya just gotta take a look down in the plug opening to tell which ones were used. Besides being "correct" for your '69, Trooper, the XLS plugs put the plug tip in the combustion chamber for improved spark introduction and increased ignition efficiency. The question now is, can you still get the XLS plugs? Chuck _______________________________________________ Chevelle-list mailing list [EMAIL PROTECTED] http://chevelles.net/mailman/listinfo/chevelle-list_chevelles.net
