273/235 Gas/Octane Requirements

The motor that's in the process of being rebuilt is a 66 273/235 motor that had a published compression ration of I think 10.5 to 1. I say the compression ratio is 10 plus as I'm using the Fel Pro gaskets rather than the stock steel gaskets. I ordered the cam from Racer Brown. We discussed at length the motor (original 273/235), transmission (4 speed), rear end gears (currently 7.25 3.23 non-SG but will be upgraded to an 8.75 with 3.23SG), headers or stock exhaust manifolds (no header), how the car was going to be used - cruiser, race or combination (cruiser). Also told him the car will be going to the Netherlands where quite a few roads speed limit is but 80 KPH (50MPH). I can't put my hands on the cam card right at the moment but it's similar to a stock 65/66 273/235 cam. My son said if it'll run on our 93 premium it should be OK on their 98 premium.