About 40 years ago, TCM (now CMI) ran an IO-520BA on their test cell with no rings installed in any of the six cylinders. It made rated power with a static compression of 0/80. It could only do so for a relatively short time, since it was blowing oil out of the breather rather quickly, but it, nonetheless, made rated power. That's why engines with low compressions due to leaking rings still produce power.
This information came to me directly from the director of the test facility at the Mobile, Alabama, TCM factory. Of, course, that's not "data", it is simply his observation…. oh, wait, that's what data is, isn't it? The observation of a phenomenon and the recording of it during a scientific test.
An opinion is a conjecture without supporting observation during a scientific test. I don't give opinions unless I so state.