Anyone using Dougs D453 headers on Magnum heads?

And I've never heard that a header gasket had a different port opening than a stock one did.

If you look on summit or jegs you can find several sets of header gaskets with different opening sizes than stock. I used Mr. Gasket ultra seal gaskets on mine with EQ heads and they didn't overlap like the stock ones you show. In fact I researched them to find a gasket that had the proper opening to match the port and header with as little difference as possible. They've been on the car now for at least 3 yrs. and no leaks