Originally Posted by
Big Pistons Forever
Yes your engine can run on UL fuels, See Lycoming Service Instruction 1070AB
I was about to post the same. The O-235-L series
can indeed run on unleaded fuel - as can the vast majority of non-turbo'd engines.
Lycoming has a whole swag of unleaded-approved engines contained in their Service Instructions -
click HERE to see if a specific engine is listed.