Lol! Back in the late 70’s I was given a YZ 400 dirt bike all taken apart (I was 12, wanted a bike and my dad sad get it t running) champions fouled every time. NGK fixed my two stroke delima. When the 273 in my 66 barracuda came home from the dyno it had Autolites in it. Owner of the shop who built it said easier to read and easier to figure out heat range.