$350 a month at the pump is about $4,200 a year — the spend level of a real commuter with a 40-mile round trip, or a household running two cars. It feels like it should call for a "gas card." It mostly doesn't.
Here is the uncomfortable math: the best dedicated gas cards earn about 4% to 6% at the pump — roughly $168 to $252 a year on $4,200 of gas. That's the entire prize for optimizing gas — and it's smaller than the credits and everyday multipliers on a good general card. So the card that wins a gas-heavy wallet is usually the one that earns well on everything *around* the gas, not the one with the biggest number at the pump.
Key insight
No card in this top five is a "gas card." The best dedicated gas rates here — U.S. Bank Altitude Connect's 4x on gas (about 4% effective at typical point value, ~$168/yr) or the Costco Anywhere Visa's 4% cash (~$168/yr) — top out under $200 on $4,200 of gas. Amex Gold earns nothing extra on gas, yet wins outright: its ~$424 in annual credits plus 4x on $300/mo groceries and $200/mo dining net about $702/yr across the whole wallet. A dedicated gas card only pulls ahead if you won't reliably use Amex's monthly credits, or you want no annual fee at all — in which case the Altitude Connect (4x gas, no annual fee) or Costco (4% gas, free with membership) are the honest answers.