Even the LL contains 1.2 to 2 grams TEL per gallon. As far as running it, with 11 to 1 you will be quite safe as long as you jet it correctly. And avgas has very good vaporization characteristics which is a good thing, if you get some do a test. Find a piece of metal to put some on along with some pump gas and if you have some racing gas. See which one vaporizes first, and which leave deposits that don't vaporize. Any that don't will be very difficult for the engine to burn. Depending on what you run currently for fuel you may need to jet up one or two jet sizes.