Announced 16 October 1956, the 105R and 105S used a high-output, 8.5:1 compression version of the "" engine used in the 90. The higher compression was to take advantage of the higher octane fuel that had become widely available. This twin-SU carburettor engine produced 108 hp (80 kW). Both 105 models also featured the exterior changes of the rest of the range announced a month earlier. The 105S featured separate front seats, a cigar lighter, chromed wheel trim rings and twin Lucas SFT 576 spotlamps. To minimise the cost of the 105R, these additional items were not standard, however they were provided on the (higher priced) 105R De Luxe.