I had an old S with vertical oil cooler and rubber unis too. An early Aus Cooper 'S'

Car Number; 935
Engine Number; 9FSay/38760

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The bitterness of poor quality (or Crappy Workmanship) remains LONG AFTER the Sweet Taste of Low Price is forgotten.

I am restoring Mk1 S No 1197 eng No 40507 Australian-built (around April-May, '66). It has rubber unis and vertical oil cooler.
Gtogreen's changeover engine number (41234) for Australian Ss is also quoted in John Sneddon's book as being in Sept '66.
Maybe 8700s14 had the whole gearbox replaced at some time. Is the casting number on the 'box 22G333?

Will have to look into it when I am back in the garage, I do remember seeing a box with a spare swivel hub and cv shaft among the parts I was given with the car, so will have to look a bit deeper and see if there are any hints there!