Know Your MGB

Know your MGB

CHASSIS (CAR) NUMBER, VIN & MAJOR UNIT SERIAL NUMBERS
The following illustrations show where the various identification/serial numbers are located on the MGB and MGB GT:

The MGB’s Timeline

MGB Roadster 1962-1980

3 Synchro (β€˜Mk 1′) 1963 to 1967 Model Years

GHN3-101 to 48766 (Jun. β€˜62 to Oct. β€˜64): 3 main bearing engine with dynamo, positive earth, 3 synchromesh gearbox.

GHN3-48767 to 138400 (Oct. β€˜64 to Oct. β€˜67): 5 main bearing engine with dynamo, positive earth, 3 synchromesh manual gearbox.

4 Synchro (β€˜Mk2 & Mk3) 1968 to 1980 Model Years

GHN4-138401 to 187209 (Nov. β€˜67 to Oct. β€˜69): 5 main bearing engine with alternator, negative earth, 4 synchromesh manual gearbox or automatic gearbox, last cars with chrome grille, last cars with BMC type interior trim with leather seats.

GHN5-187210 to 219000 (Oct. β€˜69 to Aug. β€˜70): Black recessed grille, first cars with β€˜Leylandised’ vinyl interior trim, last cars with packaway hood or deluxe folding (grey frame) hood.

GHN5-219001 to 258000 (Aug. β€˜70 to Aug. β€˜71): Black recessed grille, last cars with 18G series engines, first cars with folding (black frame) hood.

GHN5-258001 to 294250 (Aug. β€˜71 to Aug. β€˜72): Black recessed grille, first cars with 18V series engines, first cars with centre console with armrest.

GHN5-294251 to 360300 (Aug. β€˜72 to Sep. β€˜74): Chrome/black honeycombe grille, first cars with cooling slots in front valance, last cars with chrome bumpers, last cars with overdrive switch on fascia.

GHN5-360301 to 410000 (Sep. β€˜74 to Jun. β€˜76): First cars with rubber bumpers, overdrive switch on column stalk, last cars with mechanical radiator fan.

GHN5-410001 to 501000 (Jun. β€˜76 to Jun. β€˜79): Overdrive switch on gear lever, first cars with electric radiator fan, commonly called β€˜September 1976 on’ models (although the first car was built in June, the model was launched in September).

GV_DJ_AG-501001 to 523001 (Jun. β€˜79 to Oct. β€˜80): Cars with new international VIN (vehicle identification number) type serial number

MGBGT 1965-1980

3 Synchro (β€˜Mk 1’) 1965 to 1967 Model Years

GHD3-71933 to 139470 (Sep. β€˜65 to Oct. β€˜67): 5 main bearing engine with dynamo, positive earth, 3 synchromesh manual gearbox

4 Synchro (β€˜Mk 2 & Mk 3’) 1968 to 1980 Model Years

Mk 2 – GHD4-139471 to 187840 (Nov. β€˜67 to Sep. β€˜69): 5 main bearing engine with alternator, negative earth, 4 synchromesh manual gearbox or automatic gearbox, last cars with chrome grille, last cars with BMC type interior trim with leather seats.

Mk 3 – GHD5-187841 to 219000 (Sep. β€˜69 to Aug. β€˜70): Black recessed grille, first cars with β€˜Leylandised’ vinyl interior trim, horn push on column stalk.

GHD5-219002 to 258003 (Aug. β€˜70 to Aug. β€˜71): Black recessed grille, last cars with 18G series engines, horn push back on steering wheel.

GHD5-258004 to 296000 (Aug. β€˜71 to Aug. β€˜72): Black recessed grille, first cars with 18V series engines, first cars with centre console with armrest.

GHD5-296001 to 361000 (Aug. β€˜72 to Sep. β€˜74): Chrome/black honeycombe grille, first cars with cooling slots in front valance, last cars with chrome bumpers, last cars with overdrive switch on fascia.

GHD5-361001 to 410350 (Sep. β€˜74 to Jun. β€˜76): First cars with rubber bumpers, overdrive switch on column stalk, last cars with mechanical radiator fan.

GHD5-410351 to 501035 (Jun. β€˜76 to Jun. β€˜79): Overdrive switch on gear lever, first cars with electric radiator fan, commonly called β€˜September 1976 on’ models (although the first car was built in June, the model was launched in September).

GV_EJ_AG-501036 to 523002 (Jun. β€˜79 to Oct. β€˜80): Cars with new international VIN (vehicle identification number) type serial number.

MGB GT V8 1972-1976

GD2D1-101 to 2100 (Dec. β€˜72 to Sep. β€˜74): Chrome bumper models.

GD2D1-2101 to 2903 (Sep. β€˜74 to Jul. β€˜76): Rubber bumper models

Identifying your MG

To ensure the parts that you order are correct for your MGB or MGB GT, you will need to know most importantly the chassis number (models up to 1979) or VIN (vehicle Identification Number, 1980 models only). Additionally when ordering engine parts you will also need to know the engine number. Gearbox, overdrive and axle numbers may be required to order parts for those major units.

Chassis Numbers 1962-1979

Chassis number prefixes are as follows:
GHN3 MGB Roadster, 3 synchromesh, 1962-67
GHN4 MGB Roadster, 4 synchromesh, 1967-69
GHN5 MGB Roadster, 4 synchromesh, 1969-79
GHD3 MGB GT (4 cyl), 3 synchromesh, 1965-67
GHD4 MGB GT (4 cyl), 4 synchromesh, 1967-69
GHD5 MGB GT (4 cyl), 4 synchromesh, 1969-79
GD2D1 MGB GT V8, 1972-76

First character – MakeG = MG
Second character – Engine TypeH = Engine Size between 1400cc & 2000cc
Third Character – Body Type N = 2 seated Roadster
or
D = 2+2 GT (Coupe)
 Fourth Character – Series3 = Mk1 (1962-1967)
4 = Mk2 (1968-1969)
5 = Mk3 (1970- June 1979)
 Fifth Character – MarketU = USA & all left-hand drive Cars – 1970 (Mk3) onwards
L = Left-hand drive (used upto end of Mk2 Cars – Sept. 1969)
R = Right-hand drive (not used on UK Spec. cars)
Sixth Character – Model Year
(North American Market Only)
None =1968-69
A =1969-70
B =1971
C =1972
D =1973
E =1974
F =1975
G =1976
H =1977
J =1978
L =1979
 Characters Seven to TwelveIndividual Car Number
 Thirteenth Character (Mk2 Onwards)G = Built at MG Factory Abingdon

Example: A car showing GHN5UF376343G is – MG/MGB/USA spec. (Roadster body/1800cc B Series engine/LHD steering, manual gearbox/1975 model year/built Abingdon plant (MG factory)/serial no. 376343

Vehicle Identification Number (VIN) – June 1979 – October 1980

VIN (Vehicle Identification Number)
The last six characters of the VIN are the serial number of your car. However, the VIN also provides you with considerably more useful information, most importantly the model year of your car (most changes in production relate to model years). The complete VIN can be broken down thus:

First characterG = MG marque
Second characterV = MGB model range
Third CharacterA = UK spec. (Roadster)
 G = UK spec. (GT)
 J = Japan spec
 L = Canada spec.
 V = USA Federal spec.
 Z = USA California spec.
Fourth CharacterD = Roadster body
 E = GT body
Fifth CharacterJ = 1800cc B Series engine
Sixth Character1 = RHD steering, manual gearbox
 2 = LHD steering, manual gearbox
Seventh CharacterA = 1980 model year
Eighth CharacterG = Abingdon plant (MG factory)
Ninth to Fourteenth12345 = serial number Characters


Example: A car showing GVGEJ1AG 501036 is – MG/MGB/UK spec. (GT)/GT body/1800cc B Series engine/RHD steering, manual gearbox/1980 model year/Abingdon plant (MG factory)/serial no. 501036

Identifying your Engine Number

The engine number will tell you far more than just the serial number of your engine

Engine No., 18G Series, 4 Cylinder Engine 1962-71

First prefix18 = 1800cc
Second prefixG = 3 bearing crank, open crankcase breathing
 GA = 3 bearing crank, closed circuit breathing
 GB = 5 bearing crank, closed circuit breathing, dynamo
 GD = 5 bearing crank, closed circuit breathing, alternator
 GG = 5 bearing crank, carb feed breathing circuit, alternator
 GF = USA/Canada only
 GH – GK = USA/Canada only
Third prefix (optional)R = Overdrive
Fourth prefixU = 3 synchro
 We = 4 synchro
 Rc = automatic
Fifth prefixH = High compression
 L = Low compression
Remaining DigitsSerial number


Example: An engine showing 18GD R We H 6001 is – 1800cc/5 bearing crank, closed circuit breathing, alternator/overdrive/4 synchro/high compression/serial no. 6001

Engine No., 18V Series, 4 Cylinder Engine 1971-80

First prefix18V = 1800cc, in-line
Second prefix581F = Twin HS4 carbs, non-overdrive, 1971-73
 581Y = Twin HIF4 carbs, non-overdrive, export, 1971-73
 582F = Twin HS4 carbs, overdrive, 1971-73
 582Y = Twin HIF4 carbs, overdrive, export, 1971-73
 583F = Twin HS4 carbs, auto
 583Y = Twin HIF4 carbs, auto, export, 1971-
 779F = Twin HIF4 carbs, non-overdrive, 1974
 780F = Twin HIF4 carbs, overdrive, 1974
 846F = Twin HIF4 carbs, non- overdrive, rubber bumper
 847F = Twin HIF4 carbs, overdrive, rubber bumper
 584Z to 673Z = USA/Canada only
 836Z to 837Z = USA/Canada only
 797AE to 893AE = USA/Canada/Japan only
Third prefixH = High compression
 L = Low compression
Remaining DigitsSerial number


Example: An engine showing 18V 847F H 40101 is – 1800cc, in-line/twin HIF4 carbs, overdrive, rubber bumper/high compression/serial no. 40101

Engine No., 486 Series, V8 Engine 1972-76

First prefix486 = 3500cc, 8.25:1 compression ratio, MGB installation (rear mounted HIF6
carbs, remote oil filter head)
Fourth to Eighth DigitsSerial number


Example: An engine showing 48601301 is -3500cc, 8.25:1 compression ratio, MGB installation/serial no. 01301

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