I have, and run them in all my lawn equipment, they will fire anything.http://e3sparkplugs.com/
I ran these plugs in my S-Type Jag, the 4.2l V8. Went from 28 to 32 MPG on the highway. I also ran regular gas in the Jag without problems. Anyone else use/using these plugs with similar increased performance?
They are a little more expensive, but my opinion on AC Delco stuff is low, they used to be good, but the quality has really slipped.
I run those, or Bosch plugs in everything.