I've used automotive fuel almost exclusively for the 4 years I've owned my plane. The O-470 is also said to be prone to carb ice, though it has never been a problem for me. The flight school where I learned, and subsequently rented for my first 5 years as a pilot used and still uses automotive fuel exclusively in their C-150s, C-172s, PA-28, and Apache. Carb ice was never a problem, nor was vapor lock in the low wings. Now that I think of it, in 8 years as a pilot, I've only flown one airplane that doesn't run on mogas. If you have a low compression engine that can use mogas, go for it, and try not to worry about it. I primarily use 87 octane in the Skylane with good results.