Gasoline Octane Suggestions

thesiren74 said
Engine masters just did an episode on octane,87,91,106 and 110 made the same power and same timing requirements, i would use midgrade or premium.

i just watched that episode and it got me wondering if my 440 could take a lower Cali gas octane, currently running 91. I have a 10:1 compression ratio with ~38* timing
Anyone running 87 or 89 without knocking issues?