I wonder how fuel quality has changed during the time I've owned my 1984 Ski Nautique with a 351 Windsor. I've never had any memorable fuel issues, octane always has seemed adequate, and despite alarmist warnings that lead removal would cause valve recession, I've noticed no problems. The advice when lead was removed was get hardened valve seats installed, and assuredly run lead substitute if not. I didn't do either, continue to run E10 87 octane auto pump gas, and it runs great. It has almost 1700 hours on it, and appears to have the same power as the day I bought it. How has fuel changed over the last nearly 40 years beyond the obvious addition of ethanol and the removal of lead? I'll assume some aspects of fuel are worse and some are better. Possibly modern fuel is more tightly monitored and blended more consistently.