What about the fact that AV Gas contains lead while Gasoline doesn't?

It does have small amount of lead (which will destroy cat converters if equipped). Although you have 11:1 compression, you have to figure in timing (if deviating from stock) as well. This could cause an increase in detonation, requiring more octane

I used to mix it 50/50 with 93, now I run it straight and have a carb set up for it when I go to the track, I use another carb and 93 on the street

Highly unlikely, I’m a pilot as well as a racer , I’ve used AV gas in many race cars and even some of my street cars at the track never had an issue like that. I’d guess you had some crap in the tank that made its way to the needle and seat and hung it open causing a nasty rich condition from the vent tubes flowing fuel out the top. Holley? ( just a guess but common)

For those running AV gas 100LL now stock up cause it’s going away very soon. The new unleaded AV gas has been approved. Pilots are not happy about the change over I can tell you that but 100LL despite its name actually has a lot of lead in it. So it’s gone.

Keep in mind that Aviation engjnes run at about 2600 rpm’s and this fuel is designed to run that RPM sustained more than 1000 to 6000 Rpms that being said it’s always run well for my cars and lots of landscaping equipment without changes.

Many lycoming engines running av gas are low 7.9 compression. Sometimes as low as 7.0! Big bore engines.

Thought some of you may enjoy this read about AV gas and of course none of us use AV gas on the street because that would be illegal. This information on AV gas is for off-road / track purposes only

https://www.aviationsafetymagazine.c...urn-baby-burn/

I never had any problems using straight AV gas years back. My Chevelle ran just find.

I do run a 50/50 93/AvGas mix in my old 911, has a 9:1 ratio, but high RPM. It runs VERY well on this fuel set up

I ran it with Sunoco Ultra 94 … Had good results…

I had a higher compression Buick and it would ping like crazy on regular 93, putting 5 gallons of av gas to a tank eliminated the ping and never an issue with the carb.
I also ran it in my outboard drag boat with zero issues. I was told that the rating of 100 octane was a min rating and it could see higher numbers.

Perhaps there was trash in the needle and seat that I picked up from the hand held gas tank? I am familiar with the issues that trash causes in a needle and seat and my issue did appear that was the problem. I was of the mind set that I was going to have to pull the carb and clean it. But when I put the 93 in the tank and ran the engine up to 5K twice things started getting better? Perhaps I was just lucky and cleared the trash? Right now the car is running like a top and I love the smell of the AV gas.
Here in Sarasota County I can get Sunoco 90 and 100 octane non ethanol at the pump. Will likely just use that simply because of ease of filling the tank. Prior to the AV gas this is what I was running, but just wanted to try the AV Gas.