Will I break this crank?

It's a little hard to estimate the horsepower at my 3200' elevation. I'm planning on 10.5 to 1, and looking at cams now. We only have 91 Octane premium. It is easy to find ethanol free premium though. There is a 10 percent horsepower penalty at this elevation, and I am not willing to mix race gas with premium. I suppose 10.5 to 1 is more like 9.5 to one at this elevation. If I shoot for 600 hp it's likely I'll only be making 540.