Is the 383 a better engine, or does the 440 just have more displacement?

90 octane non-ethanol gas. Rec is abbreviation for recreational, as in boats, ATVs, etc. Good for most anything with a carburetor, as long as the octane is sufficiently high. Works nice in my 340. Higher than 90 is available some places, but not near me. I'm about 2 miles from a Great Lake, so easy to find. I use it in four carbureted engines.
There's a cell phone app called Pure Gas that lists stations offering non-ethanol gas based on your location. It tells you where and what is offered. Pretty handy.
No such thing in california, except for race gas. California law does not require alcohol.... but it DOES require oxygenation, and that's what alcohol does.