I've been trying to figure out what to do with my 68 460. The high compression means premium fuel and I can't afford that. While looking for some other parts I stumbled on a propane system that I had squirreled away. Ding! I have a non-running very high mileage van I use for storage that has a complete propane system. IIRC propane will support up to 13-1 compression.....the wheels are turning....
Octane = 8(oct) carbon molecules with 18 hydrogen molecules, and is a very stable chemical "string"
If there are less then 8 carbons in the "string" it becomes less stable, easier to break apart, i.e. ignite
Octane rating is the amount of stable strings in the volume
Gasoline runs 87 to 92 octane
Propane 104 to 112 octane
Octane is not power related, just the rating of 8 carbon strings
Compression is heat, it is also power, like winding a rubber band, more winding releases more power.
With too much heat low octane fuel will self ignite, so 87 octane gasoline needs 9.4:1 or lower compression ratios
Propane does have less stored energy per "gallon", but with it's higher octane rating it could be used in higher compression engines to balance that out, but then that engine couldn't run 87 octane gasoline.
Diesel uses Cetane(Hexadecane) rating, 16 carbons with 34 hydrogen also a very stable string and also harder to ignite