octane boosters?

You are on the high side of compression for pump gas. I run 11.7 and this is what I do. I can curse and drive on pump gas, but like you, I can not put a load on the engine without detonation.

When I want to run the car hard and use the power it has I put in some 110 octane race fuel. With your compression ratio 5 gallons of race fuel then fill the rest of the tank with the best pump gas you have should work fine.

This is your best and only real option IMHO.

Octane boosters don't work.