[ominous_prime]

The engines don’t require lead, it was just the only high octane fuel available. We do have a 100LL replacement now, and work is being done to get it into service. Lower compression engines run just fine on mogas where it’s available too.

[aidenn0]

They require high octane and no ethanol

[asguy]

The engines are fine with ethanol. The problem with ethanol is the issues related to it eating at materials in the fuel system (e.g. fuel lines) that aren't alcohol tolerant.