340 stroker 422

Okay, here "pump gas" premium varies depending on location from 91 to 93. 100, unleaded or leaded, is considered race gas, and is at least twice the price of pump gas.
Is your 100, just top end pump gas, compared to your 98(?) premium, or really more like race gas?
My guess is that you will need the very best pump gas, plus some kind of octane booster.