Spark Plug Recommendations?

[AndyM]

I need some opinions on what plugs I should be running in my new 3.5. Its an E28 block and head with flat-top pistons and a cam. I'm running the ignition through an MSD. I have W8DCs in there now, but should I be running WR9LS? Can anyone explain the differences? I assume the "WR" means its a resistor plug -- does that matter? Thanks

 

[Philip Slate]

A resistor plug is mainly a radio supression thing (to quiet the 'audible tach' coming through the sound system). As for which heat range to use, drive the car for awhile and then pull the plugs for a look see to asses their how they're doing.