John Sprinzel started in the 1950's with modifying his own cars and then went on to found Speedwell in 1957 along with Len Adams and George Hulbert, he then sold his sharres to Graham Hill at the end of 1959. John then established the Speed Equipment division of the Donald Healey Motor Co at Grosvenor Street in the West End of London but it only lasted a couple of years as the overheads were so high that Donald Healey decided that it was uneconomic to continue.
John then went on to set up his own company John Sprinzel Ltd, 32 Lancaster Mews, London.