Link to a reprint of an old Michael Green book online
By 1943, the U.S. Navy was preoccupied with a requirement for long-range shipboard aircraft suitable for operation against the Japanese home islands from carriers cruising in the Pacific outside the normal range of Japanese land-based aircraft. The Boeing company designed a large, multi-purpose fighter suitable for such operations and which on May 4, 1943, was awarded a prototype development contract for the XF8B-1.
The XF8B-1 was the largest and heaviest single-seat, single-piston-engined fighter developed in the U.S.A., and the twenty-eight-cylinder four-row Pratt and Whitney XR-4360-10 engine was mounted on a power egg and drove two Aeroprop three-blade contra-rotating airscrews. The XF8B-1 was intended to fulfil the roles of interceptor, long-range escort fighter, dive-bomber, torpedo-bomber and horizontal bomber.