Thank's for the help. It turns out ,Morgan, AstonMartin, Peerless & Jowett also did. & historically WWII Jeeps made a massive impression on the British car industry after the war the Salisbury/DANA became the diff of choice. I should explain what I am trying to do. I am planning to put smaller wheels on a Jowett (flat four,not inline, please don't shoot me) but then need to change the diff ratio ,to maintain the road speed. & it seem's easier to get a diff or crown set for a more common car eg Jeep or Studebaker, Rambler( all inliners) than an odd ball like Jowett or Peerless. The DANA probably also stayed in production long after Jowett ceased production. Or may share the crown & pinion with the later DANA's.