Quote Originally Posted by NFATrustGuy View Post
Be careful running 100LL in your car. The LL stands for Low Lead, but it's not actually low lead AT ALL. As a comparison, 100LL has 2 grams of lead per gallon while unleaded car gasoline has a mandated maximum of 0.1 grams of lead per gallon. All that extra lead can really gum up your valves if your car isn't designed for it.

There's a place that sells paperwork for light aircraft to use auto gas in place of 100LL. They have a great discussion of the differences between 100LL and unleaded auto gas.

http://www.autofuelstc.com/stc_specs.phtml
FYI Leaded fuel will not gum up your valves. What it will do is plug up your catalytic converter because the lead will not burn out of it. It also causes lead fouling on the spark plugs.