I have seen the new motorcycle engine's have 11.0 on the the compression, it is all about the volume you have in the engine .
My new 6.4 Challenger is 10.9
I had one of those same 6.4 SRT8s in my 2011 ram 1500 4 door 4wd but I had more compression, I had eagle heads swapped onto it that are about 10CC smaller, ran great on 91 octane (3000 foot elevation) but would knock if it even sniffed anything lower. I don't remember the exact number but I think it was around 12to1 actual.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
