Like what a few guys have already said, get rid of that swill gas you have now, and put some real gas in it.
I'm betting the compression is higher than you think. 0 deck? I would have CC the engine after I had the heads on, when I put it togeather so I knew for sure what the compression is.

Get good gas first. Like what already said, I'd start with a straight 110 leaded. You maybe be able to blend down from there, but at 11+-1 gonna need more than prem pump gas. Hopefully you have someone nearby who sells race gas at the pump or buy it by the drum. Speed and horsepower cost $$

We have a place nearby that sells 100 octane unleaded and 110 leaded at the pump, makes it nice.