The true story, that they are still trying to keep secret, is the British made a mistake with the order. Someone put 170,000 instead of 17,000. By the time the mistake was realised Packard were involved, so designs like the Lancaster, Mosquito and P-51 were ordered to soak up excess Merlin production. I read it somewhere on the net, so its true.I'm pretty sure we all know this and the myth of the 'mericans showing the British how mass production works has been debunk numerous times but alas the rumour still persists.