Crower made a camshaft for smallblock chevies years ago that had a very late-closing intake valve. It was specifically designed for higher compression ratios and pump gas. IIRC the only test had indifferent conclusions, and I believe it was from higher-than-normal reversion pulses causing the carb to go rich. It'd probably go better with fuel injection. As late as 10 years ago Crower was still trying to get rid of them, I saw them on the 'bay.

R.

The Prius engine runs at 13:1 compression on regular gas using this principle. Also Mazda's SkyActiv gasoline engine uses something similar.