[76GMC1500]

I personally don't like precious metal fine wire spark plugs, especially the iridium plugs. Sure, they last 3x as long, but cost 4x the price. For someone like me who changes their own plugs, this doesn't make financial sense. Fine wire plugs electrodes, kind of like sharp edges in your combustion chamber, run hot and can cause detonation. This is one of the reasons you'll never see a precious metal plug on a race car. The double platinum and iridium plugs have a platinum or iridium wafer bonded to the side electrode. Under detonation, it is possible to dislodge this wafer and now you have a very hard piece of metal floating around in your cylinder.

I go through a lot of spark plugs, we've got 44 cylinders in our driveway. 2 v8 trucks, 2 v8 cars, a v8 boat, a lawn mower, and 3 1 cyl motorcycles. Spark plug quality control is very good, and I see little appreciable difference between brands. I've had one bad plug, an NGK, but I believe it was dropped at some point after manufacturing. I believe NGK and AC Delco make the best plugs, but wouldn't go out of my way to buy them. If Champion is available or on sale, that is what I would buy, and did. Autolites are at the bottom of the list, but I would buy them if the price was right.