1972 Demon 340 engine mods

Cam-swap.....
or step-dome pistons
or bigger TC and maybe gears.
9.5 with aluminums is kindof cheating yourself. They will support over 185psi on pumpgas. With that 284 cam, 11/1 is not too much. The problem is getting it with a 3.31 stroke .Your looking at a total chamber volume of about 69cc. I can't see that happening and still maintaining a minimumQ. You would need specialty pistons,more swept, or an earlier ICA.
So IMO, you are probably on the most logical track.