FWIW...I have built quite a few engines......A 10.5:1 compression is fine and so is a 10:1 compression.
If you have electronic injection, then that is something completely different......The following only applies to a carb......
That is if you only want to spend $3.50 for race gas. 10:1 compression barely works with iron heads and premium pump fuel. You'll have to kill all of your timing and then you'll lose a lot of power. When you retard your timing, that will cause your engine to overheat, and your headers to glow at part throttle. Part throttle is expressway driving....
Well, you can run more compression with a dragrace cam because of a lot of overlap. But, if you want a lot of low end power, then you'll want to run a little less overlap and a lot less duration with wider centers. What that does for you is gives you more cylinder pressure at low RPM, which in turn gives you more low end torque and power....
I do get a lot of power from 9 to 9.5: compression engines. One more thought.....What happens when the oil companies lower their octane ratings again?
Gary.........::