If the Japanese had gained control of the Pacific. They still could not have out produced the United States. Furthermore, if they had attacked the Soviet Union they could have taken pressure off of their ally, Nazi Germany.
Furthermore, if they had attacked the Soviet Union they could have taken pressure off of their ally, Nazi Germany. Unlike the Finns, the Soviets ran rough shod over the Japanese in battles fought in Manchuria before Pearl Harbor, and that was without numerical advantage. The Japanese were ill prepared to fight on open country and I doubt they would have done well at any point. Even it they had, the Soviets likely would have just withdrawn from the East versus fighting on two fronts.
The Japanese Navy could not have done much to help against the Soviets. Everything I've read indicates that the Japanese wanted no part of tangling with the Soviets after those initial encounters.