Brent P
Maybe its not what you intended, but from my chair that's exactly what you did. I pointed out that high(er) compression combustion is a more thermally efficient process by a great enough degree to offset the difference in energy content in the fuel required. Then you brought up HiPo 60s v8s, which have nothing to do with the basic question.
Granted, but let's look at a pair of trivial solutions: either throttle the higher output engine, or lug it down to a lower RPM where it produces the same power as the lower CR engine does at a higher RPM. Leave the cam and fuel system alone, and just optimize the ignition timing in both cases. Which one will be more efficient? The higher CR engine, even though its throttled which costs you some potential efficiency.
Better yet, build two engines and hold everything EXCEPT compression constant, and measure the BSFC of each. The higher CR engine will produce more total power, but its BSFC will also be lower.
All true, but largely irrelevant since its plainly obvious that higher CR ALLOWS you to design a package that is more efficient overall, if that is your goal rather than higher specific power output. The counter-example of thundering 60's v8s (much as I love them- I was out driving mine yesterday!) is not really a counter-example at all because the design goal was absolutely NOT efficiency.
