[Dominik]

Is you car pinging under acceleration, or at the top end?

I had a 12.5:1 454 LS7 in one of my cars in the 90s and ran it with Euro 98 RON (US 93 MON). I slowed down the ignition advance curve using harder springs for the mechanical advance. Also, the car was very light and geared 3.54:1. So I spent little time under WOT, mid-range rpm (up to 3.500 rpm).

An "old-school" turbo mechanic, from the 70s (in Scottsdale) suggested water injection.
Probably not practical for daily use, but worth considering.

Do you have access to a chassis dyno?