1939 Crocker sold for a hammer price of $640,000

in 1936, and there was no “standard” Crocker. Every machine was bespoke; the customer specified the state of tune and engine displacement, which ranged between 62 CI and 100 CI, as the cylinder barrels were cast with extra thick walls. The 62 CI Big Twin produced 55-60 HP, which exceeded its competition by 40 percent or more. Al Crocker offered a money-back guarantee for any Crocker owner who was “beaten” by a standard Harley-Davidson or Indian, as he had built the fastest production motorcycle in the world with speeds exceeding 110 MPH a norm. Harley-Davidson introduced its first OHV V-twin—the model EL “Knucklehead”—six months after the Crocker, and 15 MPH slower.

The first 27 Crocker “Hemi” twins had hemispherical combustion chambers and “Crocker” embossed on the rocker-arm housing. Crocker then redesigned the cylinder heads with parallel valves and enclosed springs, and continually developed the heads, with two different “Hemi” castings used and four changes to the parallel-valve casting over its five-year run. The cast-aluminum fuel tanks were enlarged in 1938, making all earlier models “Small Tanks” and later models “Big Tanks.” The total production of Crockers is perhaps 72 total V-twins, as by 1942, “war work” restrictions meant Crocker could no longer produce motorcycles, and he chose not to resume production following World War II.

https://www.mecum.com/lots/LV0119-362293/1939-crocker-big-tank/

Bump starting a 1929 Harley, with a 1936 Crocker

The Harley needed the help, and the Crocker was the only motorcycle with a clear back tire not protected by a rear full fender

Photo by Bob Stokstad, who makes articles for motorcycle magazines: https://www.cycleworld.com/2010/10/01/pebble-beach-concours-delegance-special-feature#page-15