The chassis number for these model its composed of an initial fixed letter which is B, followed by a number that can go from 1 to 501 and finally two letters of which the first one determines the series of the model.

Depending on the first letter of the last two letters of your chassis number you can determine what series your car is and look up any modifications done through the range

choose your series

Release dates Car model Chassis number Modification Modification introduced at
 Nov. 46 to Jul. 47  Mark VI (MK 6)  B2AK to B254AK  Servo Damper  B70AK 
 Apr. 47 to Oct. 47    B1AJ to B247AJ  Squirt hole in connecting rods  B126AK 
       Shock absorber screwed inserts  B250AK 
       Twin ignition coils, parkerised tappets  B1AJ 
       Hardened push rods  B31AJ 
       Modified horn push button   B185AJ 
 Jun. 47 to Jan. 48  Mark VI (MK 6)  B2BH to B400BH  AC air cleaner, SC carburetter needles, strengthened wheel disc flange  B2BH 
 Sep. 47 to Mar. 48    B1BG to B401BG  Heater return tap deleted, heater drain tap added  B70BH 
       Provision for 5" dynamo  B112BH 
       Rocker cover breather  B198BH 
       Modified interior door locks B228BH 
       Increased synchro cam angles  B292BH 
       Modified distributor drive, spring ring, increased front shock absorber   B398BH 
       Loading  B185BG 
       Nebar rocker cover joint B303BG  
       Export body modifications  B321BG 
 Dec. 47 to Aug. 48  Mark VI (MK 6)  B2CF to B500CF  Aluminium tappet doors, large rear hub bearing  B2CF 
 Mar. 48 to Dec. 48    B1CD to B501CD  Bronze exhaust valve guides B26CF 
       Modified clutch thrust race  B164CF 
       Solid door striker plates  B206CF 
       Horn suppressor  B218CF 
       Dunlop jacks  B236CF 
       Wider opening radiator shutters  B320CF 
       2.4" servo balance lever  B344CF 
       5" dynamo  B426CF 
       C. & A. cylinder head gasket, accelerator countershaft guard  B1CD 
       13° brake expanders, 25° servo cams  B17CD 
       Modified coolant pump B115CD 
       Improved rubber door seals, servo protection plate  B347CD 
       Modified quicklift window stop  B363CD 
       Extended petrol tank breather  B475CD 
 Jul. 48 to May 49  Mark VI (MK 6)  B2DA to B500DA  Low lift camshaft, Lucas screen wipers, modified core plugs  B2DA 
 Oct. 48 to Jan. 49    B1DZ to B501DZ  Oil caps in No.7 journal  B62DA 
       Bench type spring drive B128DA 
       Longer upper triangle levers  B134DA 
       Short cylinder inserts B144DA 
       Rear shock damper linkage modification B200DA 
       Battery charging plug B252DA 
       Larger frontal area radiator, anti-spill valve in radiator  B270DA 
       Chromium-plated servo plate  B384DA 
       Strengthened door hinges B420DA 
       Increased diameter scuttle drain B492DA 
       3/8 in. cylinder studs B95DZ 
       N.S. front window winder B117DZ 
       Improved window run channels B131DZ 
       Square edge bearings, 1st and 3rd mot. shafts B150DZ 
       Strengthened 3rd mot. shaft splines B159DZ 
       8 1/2" deflection front springs, radiator heated de-mister, dip and switch headlamps B193DZ 
       Modified underseat heater, export features on all cars, fixed guide to front windows B237DZ 
       22 1/2° servo cams, 3" balance levers  B241DZ 
       Heater return tap re-introduced  B273DZ 
       Revised inter-shoe brake linkage B493DZ 
 Feb. 49 to Nov. 49  Mark VI (MK 6)  B2EY to B500EY  Split skirt pistons B2EY 
 Jun. 49 to Feb. 50    B1Ew to B501EW   Granodised piston rings  B120EY 
       Portable hand inspection lamp B162EY 
       Luggage boot water trap B264EY 
       Progressive bump stops B466EY 
       3/8 in. dia. rear axle bolts B1EW 
       Closer fitting tappets B57EW 
       Commonised dash B273EW 
       Forged rear spring shackle bracket B403EW 
 Sep. 49 to Mar. 50  Mark VI (MK 6)  B2FV to B500FV  Internal oil feed to distr. B2FV 
 Dec. 49 to Jul. 50    B1FU to B601FU  Longer gear lever  B138FV 
       Modified rear s.d. plates B444FV 
       Trico windscreen washer B1FU 
       Modified s.s. tube socket B244FU 
       Modified x.s. tube sockets B281FU 
 Apr. 50 to Sep. 50  Mark VI (MK 6)  B1GT to B401GT  Revised steering geometry, thicker lipped brake drums, anti-rumble brakes B1GT 
       2nd mod to rear s.d. plates B67GT 
       Four foot mounted air silencer B111GT 
       Improved rear no. plate box, revised bijur pipes to rear shackles B165GT 
       Reduced speed fan B213GT 
       Keyhole sockets on gear control B281LGT 
       One piece rear brake equlever B381GT 
 Jul. 50 to Jan. 51  Mark VI (MK 6)  B2HR to B250HR  Aluminium cam wheel, electric clock, low rate oil feed to clutch thrust, 11" clutch (light type), 3 bush rear brake equ-support, mod. starter solenoid switch B2HR 
 Jul. 50 to Mar. 51    B1HP to B251HP  Lower bush r.s.d. link deleted B11HR 
       Speedo dip warning light B31HP 
       Large bore carburetters, mod. clutch spigot bearing B83HP 
       Closer fitting 2nd & 3rd speed bushes B95HP 
       Triple pass de-mister inter. scheme B149HP 
       Longer bosses on r.s.d. plates B179HP 
 Sep. 50 to Feb. 51  Mark VI (MK 6)  B2JO to B250JO  Thicker r.s.d. plates B2KM 
 Nov. 50 to May 51    B1JN to B251JN  Mod. water pump gland ring B61JN 
 Jan. 51 to Jul. 51  Mark VI (MK 6)  B2KM to B200KM  Triple pass r.h. de-mister (final) B2KM 
 Feb. 51 to Dec. 51    B1KL to B201KL  Modified ammeter B64KM 
       New type ignition condenser B117KL 
 Mar. 51 to Sep. 51  Mark VI (MK 6)  B2LJ to B400LJ  Steel oil caps in crankshaft B40LJ 
 May 51 to Dec. 51    B1LH to B401LH  Oil feed adaptor air bottle B170LJ 
       11" heavy type clutch B300LJ 
 Jul. 51 to Jan. 52  Mark VI (MK 6)  B2MD to B400MD  3 5/8 in. bore engine, thickened crankshaft webs, full flow oil filter, twin exhaust system (r.h. cars only) B2MD 
 Sep. 51 to Feb. 52    B1MD to B401MD  Side scuttle ventilators B29MB 
       Insulated dynamo B313MB 
 Nov. 51 to May 52  Mark VI (MK 6)  B2NZ to B500NZ  Increased front damping B210NZ 
 Feb. 52 to Sep. 52    B1NY to B501NY  Twin condensers B292NZ 
       Sp carb. needles (r.h. cars only) B478NZ 
       Short dwell detent on 1st gear selector  B500NZ 
       Repositioned oil gauge conn. on crankcase B123NY 
       Stiffened clutch casing B253NY 
       3-position heater and de-mister switches, 120° opening ventilator windows, rear window de-mister B311NY 
 Apr. 52 to Jul. 52  Mark VI (MK 6)  B2PV to B300PV  Reversion to old type front wheel studs B22PV 
     B1PU to B301PU  Solid pins and shield on servo B284PV 
       Hot and cold de-mister B53PU 
       Exhaust heat shields B159PU 
       Needle rollers in clutch release levers B185PU 
       Reduced friction on steering connections B215PU