Well the 'going through the gate' expression I'm confident I've read about RAF pilots using in the early war years. It'd be interesting to know when engines were so designed to have such a throttle setting.
Wiki, but anyway...
War emergency power - Wikipedia, the free encyclopedia
So given 'pushing it through the gate' was in common usage in the BoB and that I think the recent Spitfire book commented on pilots using WEP a little too often and wearing out engines faster than expected - it doesn't sound like it was specific to the development of a particular American engine. But maybe the term 'WEP' was to describe the effect?