I ordered the "best" gasket from Sandy Olson. My original question was why don't the big 3 or 4 model A suppliers sell the gasket that a lot of people recommend. Snyders sell the 573 but not the 509. Best doesn't recommend the 573 with a stock head.
they prolly have a mountain of FelPros on the shelf they need to move. The FelPros only fit the stock head well; they fit the HC heads very poorly