Starting in 1943 with help from the Germans but never fully accepted till post-war, the combining of the Japanese/Korean/Taiwanese culture, education and western pre-fabricated mass production assembly lines, by 1948 Japan alone overtook the USA in shipbuilding and by 1952 both the USA and UK and never looked back.
Source "The Pacific Dragons" A&E documentary, 4 part series(Japan, Korea, Taiwan, Singapore) made for Economics available to universities upon application.

Question.

What if Japan(remember to include Korea and Taiwan) had employed this mass production miracle before rather than after the war instead?
What do you think would have happened?