Fuel octane on hp 273charger engine 10.5:1 compression .

I have complete bone stock internallly >>> 273 dartcharger with all the good stuff.. has the 10.5:1 compression ..
I checked the cylinder pressure with a compression tester .. engine hot with carb fully open . and numbers are between 180 -182 lbs/in. is that normal for this engine ? seems pretty high for a 10.5: engine doesn't it.
appears I would for sure need to run Premium 93 octane fuel. engine runs great !