There's a guy over on The Hamb running an old school 392 Hemi. He has a measured 13.5:1 with iron heads and a mild solid lifter cam. He runs on pump gas. No spark knock. So yes, it can be done.
And you're right. Cylinder pressure certainly isn't a good indicator for detonation, since we have so many different chamber and piston designs, so many different camshaft profiles, so many different assembly procedures, including losing all the sharp edges. Cylinder pressure is only one SMALL part of the equation.
