The "low compression" A and E models were built for 80/87 avgas. The "high compression" B and D models were built for 91/96 avgas, which I don't even remember from the 70's, or 100/130, which was green gas. Not sure that helps with your question, but I think the STC's for autogas followed the "low compression"/"high compression" line of thought when they got approval from the FAA. Will my 160hp Apache run okay on low test autogas? I suppose, but I'd be breaking an FAA rule and running afoul of my insurance company. The real question is, where do you find autogas without ethanol in it anymore? I have pretty much given up on autogas (sadly), because of this issue.

Outside that, I'm a BIG believer in autogas and have used it in the past without any trouble at all.