My opinion of the un-leaded gas, causing valve burning and seat problems, is about the same as the R-12 versus R-134a Freon systems, won't interchange hype, when 134 first came on the market. I have been running a '40 216 engine, '59 283 engine,'69 396 engine, '69 383 Mopar and '66 421 Pontiac on unleaded gas, ever since hi-test leaded gas was taken off the market. Not saying I might never have a problem, but so far no valve or head problems. Is the lead additive needed? It won't hurt, but nothing bad happens if you don't use it. This is from my personal experience, over the years, someone else may have a different opinion.
