Dallas wrote:
My C150M POH shows an approved fuel grade includes AVGAS 80.

Assuming you could find 80, how safe is it to run?

And, what are the modifications made to the fuel system to run MOGAS?

On a purely theoretical level, what would be the ramifications of
fueling up an unmodified Cessna 150 with 92 octane MOGAS?

Here's some info on a auto fuel STC.

http://autofuelstc.com