Just my two cents on this,

In 1969 leaded premium was available, now it's not.

I'd be suprised if the compression ratio actually worked out to be 10.5:1 once you get done doing all you can to make the engine move air efficiently in the intended rpm range. Equalizing the combustion chamber sizes, flycutting the pistons if needed for valve clearance, setting up the proper quench area... all these things usually drop the compression ratio a bit unless you invest in a set of aftermarket pistons and have someone massage them into the desired dome (or dish)shape and compression ratio wanted.