Just my 273 with the famous Isky E4 running through single HP exhaust from Accurate. I just figured this out. The first video was when I was running the "too cold" Autolites and the second was 10 or so years later with a warmer range of Champions. (10 year old Champions. Not that many miles though) I can hear a difference in the cleaner running Champions even though they have 10 years and 10,000+ miles.
