Boeing's Model 804 iterations began with 804-1 in February 1957 and ended with -10 on 23 December 1957. Model 804-4 was the final design entered into the WS-110A competition and lost to the North American NA-259 on 23 December 1957.
Valkyrie. North American's Mach 3 Superbomber. Dennis R. Jenkins & Tony R. Landis