best compression ratio street build?

dodge freak said

But what if the motor were to run hot, around 200-210? What if the tune is a bit lean or the fuel system not up to par and the motor gets starve of fuel at 6,000+ rpm? In cold weather the carb leans out unless its re-jetted, and you could be out late on a cold fall night once in a while. By running 10.6, which I would do also, you leave little room for error. Why shops say 9.5 for iron heads.

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Well if you build it right it won't run hot. I run a 180 t-stat and it runs at the same temp whether it is 20 or 100 outside. In my 30+ years of wrenching on cars I have never felt the need to re-jet for the winter, adjust the choke maybe. The fuel system supports the engine to well past 6000 rpm. You need to build everything right or it will fail regardless of the compression ratio. I will be passing 40,000 miles before fall on my engine so I think I got it right.

With modern closed chamber heads like the magnums the old rules of thumb are just that, old. I am quite sure I could run my engine at over 11:1 on pump gas.

I would not be a bit surprised if you set the piston down in the hole to get the compression down to 9.5:1 it would have more detonation issues that at 10.6:1 with a nice tight quench.