The following changes were made to the Sports during production. Source: Austin Parts List PubNo. 1099
- Body #501 on: Front seats changed
- Body #559 on: Doors changed, rigid hood/convertible top compartment covers replaced by canvas type
- Chassis 568605 on: new Silencer
Early Engine changes:
- to Engine 585090: Engine block "type 1": same as GS.2/GS.3 saloon
- Engine 585091 to E. 650908: Engine block "type 2": specially modified engine, with redesigned cylinder head incorporating enlarged inlet valves as used on later GS.4 Somerset and new valve springs. Also slightly higher dished type pistons were used instead of flat ones (s. Service Journals 22, p. 39)
Changes with the introduction of the GD3 model starting with Chassis 614776 on (August 1951):
- Gearbox and gear change mechanism: column change introduced
- Facia and instruments revised
- A new type of steering wheel
- Control box: RF106/2 --> RF 95
- The mounting position of the ignition coil
- Redesigned hood frame & hood
- Wing piping (stainless steel --> plastic)
- SU carburetor: to C. 614775: type 1 C. 614776 on: Type 2
- Bonnet & boot hinges (chrome -> painted car colour)
- Boot lid and boot lid handle
Shortly thereafter (the first GD3s had non-slotted wheels):
- to C. 625018/631628: Standard Wheels with 9'' front brake drums
- from C. 625019/631629 on: Slotted Wheels & 10'' front brake drums
The following modifications have been incorporated in the A 40 Sports engine to correspond with the A 40 [Somerset] saloon engine (GS.4)
Commencing Engine Number: 650909 on. [see Service Journals 22 Engine 5-8]
- Engine block "type 3": Somerset type of engine; eliminating external oil pipes by attaching the oil filter to a mounting bracket having passages drilled internally.
- New distributor with in-built vacuum control mechanism 3H2168. The adoption of this type of distributor has necessitated lowering the height distributor mounting boss and made possible the use of the A 30 distributor driving spindle and distributor fixing plate. The thread of the suction unit of the distributor is now 24 T.P.I., A.N.F., and, to agree, a new vacuum ignition control pipe is introduced.
- The ignition radio suppressor is now incorporated in the distributor cap.
- A new larger oil dipper rod and cylinder block drain tap are introduced.
- New oil filter to correspond to mounting bracket: Oil filter to E. 650908: 3H1112. New oil filter from E. 650909 on: 3H2371.