If you're running a 52 or 53 without hardened valve seats you might want to use a lead substitute, but otherwise it'll run on anything.

I just returned from a 550 mile trip and ran 85.5 octane regular unleaded with no problems including pulling hard up mountain passes with about 500 lbs in the box.

Unless your motor is built for performance - high comp heads or radical cam, you should be good with regular pump gas. IMHO