Joined: Mar 2009
Location: Travis AFB / Fairfield
Iridiums are difficult to gap because the electrode is thin and fragile. You do not HAVE to increase the gap. The extra voltage just makes it possible to do so.
Multi-ground plugs, such as E3's, shroud the spark. All those extra grounds serve only to obstruct whichever one is doing work at a given moment.
I would recommend the NGK platinums for a stock or mild car(iridium is essentially the same, just more expensive...). I would only use coppers in vehicles with forced induction or high-strung NA engines. They errode quickly, requiring regapping and replacement to a point that makes them just as expensive as platinum.
1995 5.0L GT, T-5, Black, 'vert.
1996 4.6L GT, T-45, Laser Red, 'vert.
1997 3.8L V6, 4R70W, Laser Red, coupé.
1997 3.8L V6, T-5, Black, coupé w/ sunroof.
1997 4.6L Cobra, T-45, Black, coupé.