This Identification guide has been written to assist people in determining the authenticity of an Australian MK1 Morris Cooper S. For the MK2 Australian Cooper S, click here. The Australian MK1 variant of the Cooper S had a number of unique features when compared to other Mini models, and these are explained in detail below, including information with respect to correct engine and chassis number identification.


The MK1 Morris Cooper S had the largest production numbers of the Australian produced Cooper S cars, and is a highly desirable car in Australia and internationally, due to the unique and arguably improved features applied. Values of the Morris Cooper S have skyrocketed in recent years, and as a result, information regarding the accurate identity of these cars is essential, as they are closely related to the standard Minis of the same era, with many replicas produced. This guide provides a detailed outline, with associated images, to assist a prospective purchaser or owner in accurately identifying a vehicle. 

Number produced: Approximately 4,986 MK1 Cooper S cars were produced. Approximately 7,500 Cooper S cars in Australia were produced in total (both MK1 and MK2).

Period of manufacture: September 1965 – April 1969. Note, there was partial overlap with MK2 production, and often components of both series cars may be seen on both around the changeover period. Where possible, these items have been detailed in this guide.

Please note, this guide has been written based on a variety of online sources and enthusiast input. You should not rely on this guide to make any purchasing decision and we make no representation that all information is accurate. You should always seek independent professional advice when looking to purchase a unique car. If you have additional information, photographs or corrections you believe need to be made to this page, please contact us by clicking the button at the top of this page, or comment below. 

1. External Body Features - Morris Mini Cooper S MK1 (Australia)

The Australian MK1 Cooper S had the following external features. Note, many features are shared with the standard Morris Mini, and MK2 Cooper S. This has been noted where appropriate.

  • Based on the Mini MK1 body (as was retained throughout all Australian Mini production), with external hinges on the doors.
  • Stainless steel overriders and corner 'nerf bars' on front and rear bumpers.
  • Steel 4.5" x 10" wheels with 9 ventilation holes around the inner hub. Wheels were painted 'Silver Birch' - paint code: 06968, and fitted with Dunlop radial ply SP41 145X10 tyres. Original wheels should have a casting mark "LP883".
  • Front quarter windows and wind up windows applied to all Australian Cooper S cars.
  • The MK1 was available in two tone and single tone colour schemes (see the paint code section of this guide for more details).
  • Twin fuel tanks, filler caps visible left + right of boot.
  • Rear boot lid badging reads “Morris Cooper” with the “s” badge above in the centre of the bootlid (above the number plate). This is the same as appears on the MK2.
  • In contrast to the MK2 Cooper S, the MK1 retains the standard Morris front hood badge, with a small "S" badge above.
  • In contrast to the MK2 Cooper S, the majority of MK1 cars were not fitted with wheel arches / flares as standard, however, this is a common aftermarket modification. It is generally accepted, however, that the MK1 could be dealer fitted with flares, and this is believed to have more commonly occurred in South Australia and Victoria.
  • Commonly fitted with aftermarket period 'Contessa' / 'Minilite' style 10" wheels or Dunlop alloys, as demonstrated in several images (examples provided in the images).
2. Interior Features - Morris Mini Cooper S MK1 (Australia)

The Australian Morris Cooper S MK1 had the following original interior features:

  • Three point seatbelts were standard on the front seats only. The rear seat had no belts.
  • Boot lid internal lining: Cooper S cars had a hardcover vinyl type lining over the inner bootlid, held in place with small chrome screws and upholstery washers.
  • Instrument cluster included a 120 MPH speedometer, a temperature gauge and an oil pressure gauge. The speedometer had a black face (as opposed to the grey face of the MK2), with slightly different details when inspected closely. The shroud around the cluster is plastic, and should have 4 exposed screws on the fascia (different to the MK2).
  • Indicator light on MK1 cars is present on the end of the indicator stalk, as opposed to within the instrument binnacle on the MK2.
  • Vinyl covered dash rails top and bottom. Note, if a car is restored, these may have been re-done, but can be easily removed and may therefore be missing. This is a feature of the MK1 and MK2.
  • Chrome solid top ashtray in front upper dash rail (as opposed to the standard vented top tray applied to other Minis.
  • Single lever Smiths Heater Assembly (See images) which has a metal body (as opposed to the plastic body heaters applied to the MK2). These Smiths heaters should be attached to the bulk head under the dash, and have two J shaped hooks holding the unit. These mounting hooks should be spot welded to the bulkhead (not riveted).
  • Lower dash switches include heater cable on left, extended ignition switch in centre (The chrome body of the ignition switch sticks out more into the car than on earlier Mini's), and choke cable on the right.
  • Steering wheel originally was a 2 spoke wheel, with a M on a red background.
  • Boot board, resting on support brackets between the two fuel tanks (some reportedly originally trimmed the same colour as the seats, but commonly done in black).
  • Felt trim glued underneath the rear parcel shelf (unique to the Cooper S).
  • Heel mat built into driver's footwell carpet. (See the next section of this guide for confirmation of the correct type).
3. Interior and seat Trim Colours and Carpet - Morris Mini Cooper S MK1 (Australia)

Interior colours and codes - MK1 Cooper S:

The following interior colours and associated codes are believed to be available on the Australian MK1 Cooper S. These colours were generally applied to the seats, door cards, dashboard backing trim and carpet. The roof lining was available in cream or black. Note, specific codes for these colours are yet to be confirmed. If you have any information, please contact us.

Colour Name Colour Code
Black TBC
Blue TBC
Green TBC
Doeskin TBC


Seat trim pattern:

The MK1 Cooper S had two pattern designs, as described below and in the attached images:

  • 1965 - 1967 = Evenly spaced pleats with a thick squab at the front edge.
  • 1967 - 1969 = Wider pleats on the outer edges, and the pleats run over the front edge of the seat (as opposed to a front squab).


​Carpet types - MK1 Cooper S:

Our research suggests that carpet types varied on the MK1 Cooper S per the following points:

  • Most Mk1 cars were fitted with the ‘Westminster’ carpets. This is a 'Sisal' style loop carpet in appearance (i.e. the loops are in tighter and straighter rows than traditional loop pile carpets). On the original carpet, there should be a “Westminster” watermark on the hessian underlay (See images).
  • Some late MK1 cars were reportedly fitted with the more open loop pile carpet, as was also applied to the majority of MK2 Cooper S cars. This had a similar hessian underlining, but without the watermark. 
  • Heel mat styles built into the carpets varied. In most cases the pattern framed mat style was applied to MK1 cars. However, several late MK1 cars reported having the MK2 grid style mat design.



4. Original Paint Codes and Interior Trim - Morris Mini Cooper S MK1 (Australia)

From our research, we have ascertained that the Australian Morris Cooper S MK1 was available in the following colours in the respective years, noting that many cars had a two tone paint scheme. Should you know of any additional colours, or have images of examples you can provide to us, please contact us so we can update this section. The original colour for a MK1 Morris Cooper S will be embossed in the ID plate, the location of which is demonstrated in the images.

Colour Name Colour Code Colour Brand MK1 Availability Notes
Black TBC Dulon/Duco 1965 - 1969  
British Racing Green 00036 Dulon/Duco 1965 - 1966  
Burgundy / Burgundy Red 08999 Dulon/Duco 1966 - 1969  
Castrol Racing Green TBC Dulon/Duco 1967 One off
Cedar Green 06543 Dulon/Duco 1965 - 1966  
Clay Beige 10082 Dulon/Duco 1967 - 1968  
Crystal White 11572 Dulon/Duco 1969  
Daffodil Yellow 10618 Dulon/Duco 1968  
Dream Blue 08444 Dulon/Duco 1965 - 1966  
GTO Green 10238 Dulon/Duco 1968 - 1969  
Indigo Blue 10084 Dulon/Duco 1967 - 1969  
Jay Blue 10085 Dulon/Duco 1967 - 1968  
Kelp Beige 10087 Dulon/Duco 1967 - 1968  
Lake Green 10083 Dulon/Duco 1967 - 1969  
Malmo Green 10081 Dulon/Duco 1967 - 1968  
Marine Blue 08449 Dulon/Duco 1965 - 1967  
Neutral Grey 08450 Dulon/Duco 1965 - 1967  
New BRG TBC Dulon/Duco    
New Cedar Green 01322 Dulon/Duco 1966  
Nurburg White 02191 Dulon/Duco 1965 - 1966  
Royal Red 08451 Dulon/Duco 1965  
Sand Beige 07187 Dulon/Duco 1965 - 1966  
Sandown Red 10886 Dulon/Duco 1968 - 1969  
Sapphire Blue 10245 Dulon/Duco 1968 - 1969  
Seamist Green 01212 Dulon/Duco 1966 - 1967  
Shadow Blue 05044 Dulon/Duco 1966 - 1967  
Sierra Beige 10875 Dulon/Duco 1968 - 1969  
Sky Blue 09921 Dulon/Duco 1965 - 1966  
Snow White 10080 Dulon/Duco 1967 - 1969  
Special Burgundy 10086 Dulon/Duco 1966 - 1969  
Toga White 08452 Dulon/Duco 1965 - 1968  


5. Chassis Number / Car Number and Body Number - Morris Mini Cooper S MK1 (Australia)

Chassis prefix:

The correct chassis number prefix on an Australian MK1 Cooper S is YKG2S2. This number should be embossed on the aluminium ID tag / chassis plate, next to the heading "TYPE". The chassis plate is located on the driver's side firewall / bulkhead, as shown in the images.


Car number / chassis number:

The chassis number is also embossed on the chassis plate next to the heading "CAR NO". This is the unique chassis number of the car, and that same number should be stamped into the firewall/bulkhead panel, just below the chassis plate, as shown in the images.


Body number:

The Body Number is a unique number which is stamped only into the top of the radiator shroud panel (inner quarter panel), and is not listed on the chassis plate or elsewhere on the car. The body number does however relate to the chassis number / car number in that it should be approximately 500 less than the car number / chassis number. On the radiator shroud you should also see "M2" over "06", and then a 4 digit Body Number close by. The M2/06 confirms the body is a Cooper S, and the body number being within the approximate range of 500 less than the chassis number should confirm the body is original (noting of course that accidents can cause the quarter panels to be replaced). The stamping locations of these numbers on the radiator shroud were not always perfectly consistent in terms of location or stamping quality, as demonstrated by the attached images.

6. Engine Number and Block Features - Morris Mini Cooper S MK1 (Australia)

Australian MK1 Cooper S Engine Number:

The correct prefix on an Australian MK1 Cooper S should begin with "9FSAY", followed by a unique engine number, usually 6 digits. This prefix applies to the majority of MK1 cars, unless part of a late small batch of 48 MK1 cars fitted with the MK2 gearbox, in which case the correct prefix is "9FXEY" (see gearbox section for further details).

The engine number is located on the top of the engine block, just above the generator, and directly under the number 1 spark plug. You will see a flat area of metal, where the number is punched in. Australian Cooper S cars always had the number punched into the block, as opposed to a tag which appeared on many overseas models. The above prefix confirms that the block is a 1275 MK1 cooper S engine, but does not confirm whether the head, gearbox or other components have been changed. See the attached image for an example of the engine number appearance and location.

Engine block casting number & 'thin flange':

All Cooper S motors (MK1 and MK2) will have "AEG312" cast into the rear lower RHS of the block. Other than a small number of late cars, the MK1 Cooper S had what was known as a 'thin flange' engine block, referring to the relatively thinner area where the engine block meets the gearbox, as compared to the MK2 block. The MK1 thin flange block is approximately 10mm thick (vs the MK2 at 20mm).

Other engine block features:

  • Blocked off mechanical fuel pump hole on rear of block.
  • Removable tappet chest covers on rear of engine (as opposed to later 1275 engines where the engine block rear wall was solid).
  • Welch (core) plugs in engine block were 1 11/16 in size.
  • Block painted green. Note, engines were painted a dark green believed to be "British Standard Middle Bronze Green (Code BS 223) before they were imported as complete units to Australia. Once in Australia, most engines were re-painted to the Cooper S metallic green (Code CP8689 by Berger Paints), however, there are reportedly many MK1 exceptions which retained their original dark green paint. Please contact us if you have any further information on engine paints.
7. Gearbox Numbers and features - Morris Mini Cooper S MK1 (Australia)

Australian MK1 Cooper S Gearbox Casting Number:

The gearbox in a MK1 has synchromesh on 3 gears (gears 2 - 4), as opposed to the full synchromesh box of the MK2. However, some discussion on forums and historical documents confirm that 48 of the late MK1 Cooper S cars were in fact fitted with the MK2 full synchro gearbox. The chassis numbers to which this applied are identified in the document attached in the images.

The correct number to be cast into the majority of MK1 gearboxes (other than those last 40 mentioned above) is 22G333. This confirms that the gearbox is the correct 4 speed, 3 synchro B type remote shift, as applied to the MK1 Cooper S.

  • Casting code "Y 22G333" was applied to very early Cooper S engines (with rubber universal joints) up to 9FSAY41233, with a 3.44 diff ratio.
  • Casting code "Q 22G333" was applied to the majority of Cooper S engines (with Hardy Spicer universal joints) from 9FSAY41234 with a 3.44 diff ratio.
  • Casting code "22G1128" applied to 48 of the late MK1 Cooper S cars (per the chassis numbers listed in the attached images).


The majority of MK1 Cooper S cars were fitted with 'Hardy Spicer' universal joints (see images), as opposed to the rubber knuckle joints used on other Minis of the same era. The gearbox was also 'remote change', and contained the long mechanism as shown in the images. Note however, that some pre-1966 Cooper S cars may have been fitted with rubber knuckle CV joints, and we understand these were changed to the Hardy Spicer joints in approximately April 1966.


Serial Number: 

The gearbox may also have a unique serial number stamped into it, which will specifically confirm whether it is from a MK1 Cooper S. The correct serial number prefix, if applicable, is "12FA".

8. Mechanical Features - Morris Mini Cooper S MK1 (Australia)

The Australian Morris Mini MK1 Cooper S had the following original mechanical features:

  • The correct engine head should have a casting mark "12G940". Cylinder head has 10 nuts and 1 bolt (adjacent to thermostat housing).
  • Generator (in place of alternator as applied to the MK2).
  • High capacity SU electric fuel pump (located left side on the rear subframe, under the car). Mechanical pump on engine block removed / blanked off.
  • Hydrolastic suspension (evidenced by the fluid line hoses exiting above suspension towers and fluid lines running underneath the floor pans).
  • Oil cooler. On the first 1400 (approx) Cooper S cars, the oil cooler was a 9 row unit mounted vertically below the generator on the engine, not on the grille support brace panel. The majority of MK1 cars had a 13 row oil cooler mounted on the angled support panel behind the grille (see images).
  • Twin 1 ¼ SU carburettors. The MK1 carburettors should have small tags attached to the float bowl top screws, one with "AUD146 L" and the other with "AUD146 R" stamped into them.
  • Round edged air filter housing assembly containing 2 round air filters (as opposed to the MK2 which had a squared off edge).
  • 7 ½ inch front disc brakes. 
  • The original rear brake drums were wider by 1” (called 'stepped drums') and the brake pedal is thicker than the standard mini, and thicker than the clutch.
  • Master cylinders on the MK1 were two small tin Mowog units. However, many of these may have been replaced over time with the later plastic 'PBR' units.
  • 'Lockheed' brand brake booster (as opposed to the later VH44 'PBR' brake power booster fitted to most MK2 cars).
  • Fuel pump breather valve located under rear seat on passenger side of vehicle.
  • Additional wire on rear wiring loom running to the rear electric fuel pump.
  • All Australian MK1 Cooper S Minis had twin fuel tanks.
  • Hardy Spicer universal joints. Note however, that pre 1966 Cooper S cars may have rubber drive couplings, which from our research we understand were changed to the Hardy Spicer CV joints around April 1966.


9. Unique body features - Morris Mini Cooper S MK1 (Australia)

Several factory body modifications were made to the MK1 Cooper S which are essential for accurate identification. Some of these features are outlined below:

  • In the boot, there should be two holes on each side of the boot floor. The holes on the left are for the fuel supply hose and the fuel vapour pipe, and on the right for the battery cable and the fuel vapour pipe.
  • There should be two support brackets on the rear seat back (in the boot), as well as supports at the rear edge of the boot, to accommodate the boot board. See images for a better description.
  • Metal keeper tabs spot welded on the rear bulkhead (back seat panel in the boot area) for the fuel vapour pipes. There should be 2 tabs vertically for each tank and 3 across the top of the 'bulkhead' / rear of seat. However, some very early cars (believed to be very few in 1965) did not have these spot welded in place, and instead had pre drilled holes allowing for small clips to be attached to the bulkhead (see images of the early example).
  • Under the R/H tank there is a support bracket that should be spot welded in place (not riveted).
  • Tunnels in the floor pans, with covers for the hydrolastic lines are believed to have been introduced from 1967. Cars prior to 1967 therefore may not have had these tunnels. Also, these tunnels were not unique to the Cooper S only in Australia, and only serve to differentiate the Australian cars from other markets.
  • Looking under the passenger side rear back seat, you should see a small white plug (which looks like it's segmented into three). This is the fuel pump breather vent, again, unique to the Cooper S (most other Minis had mechanical fuel pumps on the engine block). See images for an example. Normally, this plug is a standard plastic white colour.
  • Diagonal support brace (spot welded) running behind the grille to accommodate the oil cooler. Standard mini's have a vertical metal strap rather than diagonal. As noted under mechanical features, early cars may not have this bracket as the oil cooler was mounted on the engine.
  • Two brackets / J shaped hooks which hold the Smiths heater should be spot welded (not riveted) to the interior side of the bulkhead (see images).
References - Morris Mini Cooper S MK1 (Australia)

The following sources, among input from many enthusiasts, have contributed to the creation of this page. If you have any further information you believe can be added, please let us know by contacting us or commenting below.

Special thanks to and The BMC Experience.