ive been at 12.2 to one with my 606 cu hemi runs on 93 octane no problems , but the big motors with good heads don't like much timming either that helps out

606 hemi pump gas best 9.60 at 142mph on motor
05 hemi daytona 1500 go-mango 4wd quadcab
2007 hotrod mag pump gas drags runner up, roadkill nights dodge big tire winner 2018 2019 back to back