Lets discuss another engine build

You'll want to make sure of the actual compression ratio as was noted. But I don't see a problem with the XE268 at 9.5:1 actual. I've run more than that with them before. It's not a big deal as in no special timing tricks or anything, but you will probably want to run at least mid-grade fuel if it's 10% ethanol like what we have locally.

The plus side is we have 93 Octane non-ethanol here, and I've been running that in the car.