I have heard the same thing about my 61. My friend was telling me that since my truck was built in the days of leaded gas it had "soft" valve seats. He claimed that newer vehicles designed for unleaded fuels have "hard" valve seats. I am not sure if he is right or not but he was sure that he was. I run unleaded gas in my truck and have for years, no problems yet. I put fuel conditioner through it once in a while, but nothing serious, just cheap NAPA stuff. I do that about every oil change or so. I am not sure if it does anything but I feel better about it.
