Drivetrain Decoding

©2014, Full-Size Chevrolet Research Group
Edited by Warren Leunig
Version: Thursday, 12-Nov-2015 09:33:20 EDT

Engine Pad Information

  1. Engine Pad
  2. 1964 Engine Suffix Codes
  3. 1965 Engine Suffix Codes
  4. 1966 Engine Suffix Codes
  5. 1967 Engine Suffix Codes
  6. 1968 Engine Suffix Codes
  7. 1969 Engine Suffix Codes
  8. 1970 Engine Suffix Codes
  9. Block Casting Number

Transmission Information

  1. Transmission Codes
  2. Rear Axle Numbers

Engine Pad

The engine pad was stamped with the engine assembly plant, assembly date and application code.  The location of that code was behind the distributor on L6 engines and in front of the passenger’s side cylinder head on V8’s.

Typical Engine Pad

enginepad_6Y204760_T0404IGR

The format of the engine code remained the same from 1964 through 1970.  Plant-Month-Day-Application suffix code

There were four plants that produced engines for the fullsize cars.
F – Flint, Michigan (L6 and small block V8)
K – McKinnon Industries, Canada (L6 and small block V8)
T – Tonawanda, NY (small block and big block V8)
V – Flint, MI (small block V8 starting 1967)

In the above example:
T – Tonawanda, NY engine plant
04 – April
04 – 4th day of the month
IG – 396/325HP engine with Powerglide 400 transmission
R – Rochester carburetor (Carb designation used only in 66)
6Y204760 – partial VIN# from a fullsize Chevy built at Wilmington, DE

From 1964-1967, the partial VIN# on the block was stamped on all engines with at least 300HP.  In 1968, all V8’s had the partial VIN# stamped on the block.

 

 

 

 


1964 Engine Application Suffix Codes
                                PowerGlide       3 speed 
                               A/C   no-A/C    A/C  no-A/C
                              ------ ------   ------ ------
 230ci/140HP base L6            BQ    B         AF     A
 230ci Low Compression          BS    BA        AL     AC
 230ci H.D. Clutch              --    --        AG     AE
 230ci Low Comp. & H.D. Clutch  --    --        AM     AD
 230ci Taxi                     --    BB        --     AQ
 230ci Taxi & Low Compression   --    BV        --     AN
 230ci Right Hand Drive         --    B         --     AB
 230ci RHD & Low Compression    --    BA        --     AH
 230ci COPO 9645                --    --        --     AU
 230ci COPO 9801 (Taxi w/A/C)   --    WG        --     AV
 230ci COPO 9804                --    WF        --     AW
  *B and AM also used for RHD     
                       
                            PowerGlide        Manual
                           -------------   -----------  
 283ci/195HP base V8            D               C
 283ci Right Hand Drive         D               CA      
 283ci Low Compression          DA              CE
 283ci RHD & Low Comp.          DA              CV
 283ci H.D. Chassis             --              CB
 283ci COPO 9588                DG              --
 283ci COPO 9596                --              CC
 283ci COPO 9631                DD              CM
 283ci COPO 9645                --              CW      
 327ci/250HP L30                S               R       
 327ci RHD                      SH              --
 327ci COPO 9557 (240HP)        --              RS
 327ci COPO 9588                SN/SP            RY
 327ci COPO 9590                --              RZ
 327ci COPO 9596                SQ              --
 327ci COPO 9631                SM/ST           RH/RJ
 327ci COPO 9645                --           RG/RM/RN
 327ci/300HP L74                SB              RB

                             PowerGlide        Manual
                           -------------   -----------  
 409ci/340HP L33                QG              QC
 409ci L33 T.I. Ign.            QR              QQ
 409ci L33 COPO 9645            --              QS
 409ci/400HP L31                --              QA
 409ci L31 T.I. Ign.            --              QN
 409ci/425HP L31/L80            --              QB
 409ci L31/L80 T.I. Ign.        --              QP



1965 Engine Application Suffix Codes
                               PowerGlide       3 speed 
                               A/C   no-A/C    A/C  no-A/C
                              ------ ------   ------ ------
 230ci/140HP base L6            FR    FM        FL     FA
 230ci Taxi                     --    FK        --     FP
 230ci H.D. Clutch              --    --        FF     FE    
                       
                            PowerGlide        Manual
                           -------------   -----------  
 283ci/195HP base V8            GF              GA
 283ci Right Hand Drive         GH              GB      
 283ci Low Compression          GG              GD
 283ci RHD & Low Comp.          GI              GE
 283ci H.D. Chassis or M20      --              GC
 283ci COPO 9565?               --              GM
 283ci COPO 9645                --              GJ
 283ci COPO 9670                --              GY
 283ci/220HP L77                GL              GK      
 327ci/250HP L30                HC              HA       
 327ci/300HP L74                HD              HB

                            PowerGlide        TH400          Manual
                           -------------   -----------    ------------
 396ci/325HP L35 Roch. Carb     IG             IV           IA
 396ci Holley Carb              LB             LC           IV
 396ci Transistor Ignition      II             IC           IW
 396ci/425HP L78                --             --           IE        
 
                             PowerGlide        Manual
                           -------------   -----------  
 409ci/340HP L33                JE              JB
 409ci L33 T.I. Ign.            JF              JC
 409ci/400HP L31                --              JA
 409ci L31 T.I. Ign.            --              JD




1966 Engine Application Suffix Codes
                               PowerGlide       3 speed 
                               A/C   no-A/C    A/C  no-A/C
                              ------ ------   ------ ------
  without K19 (smog)
 250ci/155HP base L6            FR    FM        FL     FA
 230ci Taxi                     --    FK        --     FP
 230ci H.D. Clutch              --    --        FF     FE  

  with K19 (smog)
 250ci/155HP base L6            GQ    GP        FY     FV
 230ci Taxi                     --    GR        --     FZ  
                       
                            PowerGlide        TH400        Manual
                           -------------   -----------   ----------
  without K19 (smog)
 283ci/195HP base V8            GF              --           GA
 283ci Right Hand Drive         GH              --           GB      
 283ci Low Compression          GG              --           GD
 283ci RHD & Low Comp.          GI              --           GE
 283ci H.D. Chassis or M20      --              --           GC
 283ci H.D. Clutch              --              --           GU
 283ci COPO 9591                --              --           GN
 283ci/220HP L77                GL              --           GW
 283ci L77 H.D. Clutch          --              --           GV
 327ci/275HP L30                HC              --           HA
 327ci H.D. Clutch              --              --          HE/KE?
 327ci COPO 9669                HY              --           --
 327ci COPO 9818 (230HP)        --              --           HZ

 396ci/325HP L35                IG              IV           IA
 427ci/390HP L36                --              IJ           IH
 427ci/425HP L72                --              --           ID

with K19 (smog)
 283ci/195HP base V8            GT              --           GK
 283ci H.D. Chassis or M20      --              --           GS
 283ci/220HP L77                GZ              --           GX
 327ci/275HP L30                HF              --           HB

 396ci/325HP L35                IC              IN           IB
 427ci/390HP L36                --              IO           II
 


1967 Engine Application Suffix Codes
                               PowerGlide       3 speed 
                               A/C   no-A/C    A/C  no-A/C
                              ------ ------   ------ ------
  without K19 (smog)
 250ci/155HP base L6            FR    FM        FL     FA
 230ci Taxi                     --    FP        --     FK
 230ci H.D. Clutch              --    --        FF     FE
 230ci COPO 9???                --    FW        --     ??        

  with K19 (smog)
 250ci/155HP base L6            GQ    GP        FY     FV
 230ci Taxi                     --    GR        --     FZ  
                       
                            PowerGlide        TH400        Manual
                           -------------   -----------   ----------
  without K19 (smog)
 283ci/195HP base V8            GF              --           GA
 283ci Right Hand Drive         GH              --           GB      
 283ci Low Compression          GG              --           GD
 283ci RHD & Low Comp.          GI              --           GE
 283ci H.D. Chassis or M20      --              --           GC
 283ci H.D. Clutch              --              --           GU
 283ci COPO 9591                --              --           GN
 327ci/275HP L30                HC              KL           HA
 327ci H.D. Clutch/COPO 9819    --              --           KE
 327ci COPO 9569               HK/KJ            --         KI/KK
 327ci COPO 9610                HG              --           --
 327ci COPO 9670                --              --           HU
 327ci COPO 9818 (240HP)        HY (with 9669)  --           HZ
 327ci COPO 9819                --              --           KA

 396ci/325HP L35                IG              IV           IA
 396ci COPO 9565 (313HP)        IY?             IW           --
 396ci COPO 9627                ??              JI           JJ?
 427ci/390HP L36                --              IJ           IH
 427ci L36 SS427?               --              IS           IE
 427ci/425HP L72*               --              --           ID
  no 67 ID motors were installed in cars according to records

with K19 (smog)
 283ci/195HP base V8           GO/GT            --           GK
 283ci H.D. Chassis or M20      --              --           GS
 283ci/220HP L77                GZ              --           GX
 327ci/275HP L30                HF              KM           HB

 396ci/325HP L35                IC              IN           IB
 427ci/385HP L36                --              IO           II
 427ci SS427?                   --              IF           IX
 427ci COPO 9627                --              JL?          JK?
 427ci/425HP L72*               --              --           IK
  no 67 IK motors were installed in cars according to records
 


1968 Engine Application Suffix Codes
                               PowerGlide       3 speed 
                               A/C   no-A/C    A/C  no-A/C
                              ------ ------   ------ ------
 250ci/155HP base L6            CR    CQ       CC/CN  CA/CM
 230ci Taxi/Police?             CT    CL        CS     CB
 230ci H.D. Clutch              --    --        CK     CJ     
                       
                            PowerGlide        TH400        Manual         TH350
                           -------------   -----------   ----------    -----------

 307ci/200HP base V8           DR/DH           DS/DK        DO/DU?
 307ci H.D. Clutch              --              --           DQ
 307ci COPO 9???                D2              --           --
 307ci COPO 9627                D4              D5?          D6?
 307ci COPO 9565??             DG/DJ            DL           --
 307ci COPO 9???                H3              --           --
 327ci/250HP L73               HJ/HK           HM/HN         HI
 327ci H.D. Clutch              --              --           HL
 327ci COPO 9665                --              --           --            HR*

 327ci/275HP L30               HC/HG           HF/HH         HA
 327ci H.D. Clutch              --              --           HB
 327ci COPO 9665                --              --           --            HS*


 396ci/325HP L35                IG              IV           IA
 396ci Police                   IN              IF           IK
 396ci COPO 9565 (313HP)        IY?             IW           --
 396ci COPO 9559 (IZ, I2, I3, I4)
 396ci COPO 9627 (I5, JB)
 427ci/385HP L36                --              IJ           IH
 427ci L36 SS427?               --              IS           IE
 427ci L36 COPO 9626 (I6, I8)
 427ci/425HP L72                --              --           ID

* Engine code for L73 and L30 with TH350, used in 
   late-year 1968 TH350 test fleet
 


1969 Engine Application Suffix Codes
                        PowerGlide        TH350         3 speed 
                       A/C   no-A/C    A/C   no-A/C   A/C  no-A/C
                      ------ ------   ------ ------  ------ ------
 250ci/155HP base L6    ??     BB       ??     ??      BG     BA
 250ci Taxi/Police      BO    BJ/BL     ??     ??      BQ     BP
                       
                       PowerGlide        TH350           TH400           Manual
                      -------------   -----------     -----------    ------------
 327ci/235HP base V8    FB/F2/F5        FC/F3/F4          FH             FA/FW
 327ci Low Compression     FN              --             --              FM
 327ci Taxi/Police       FZ/F6           GA/F7          GB/F8            FG/FY*
 350ci/250HP L65           HL              HM             HJ              HI
 350ci L65 Police          IM              IN             IP              IL
 350ci/265HP LM1           HU              HV             IA              HT
 350ci LM1 Police          IX              IY             IZ              IW
 350ci/300HP L48           HK              HN           HH/IB?            HG
 350ci L48 Police          IS              IT             IV              IR

                                         TH400          Manual
                                       ---------       --------
 396ci/265HP L66           J2 (P/G)        JQ             JN  
 396ci Police                              JO             JP      
 427ci/335HP LS1                           LE             LB
 427ci LS1 Police                          LJ             LK
 427ci/390HP L36                           LC             LA
 427ci L36 SS427 (Z24)                     LI             LH
 427ci L36 Police                          LF             LG
 427ci/427HP L72                           LS             LD

 

 327 suffix codes with a letter and number indicate usage of a revised distributor.
 FG Police only. FY Taxi only. 
 Engine Codes Reserved for Use With MA6 Heavy-Duty Clutch 
 (none known to have been produced):
 L48 - HO, IQ.  L66 - JT, JR.  LS1 - MA, LY.  L36 - MB, MC, LZ.  L72 - MD


1970 Engine Application Suffix Codes
                        PowerGlide        TH350        3 speed 
                       ------------   ------------  -----------
 250ci/155HP base L6       CCG             CCH?          CCI
 250ci Taxi/Police         CCM             CCK           CCL
                       
                       PowerGlide        TH350          Manual
                      -------------   -----------     -----------
 350ci/250HP L65           CNU            CNV            CNO
 350ci Police              CNW            CNX            ???
 350ci Low Compression     CNZ            ---            CNY

 350ci/300HP L48           ---            CNR            CNQ
 350ci Police              CNS            CNT            CNP
 400ci/265HP LF6           ---            CGR            ---    

                          TH400
                        ---------
 454ci/345HP LS4           CGV
 454ci Police              CGS
  
 454ci/390HP LS5           CGU
 454ci Police              CGT


Block Casting Number

Here are the engine block casting numbers used for small blocks and big blocks. The casting date on the L6 block is on the right side. It is located on the rear, top left (driver’s side) for all others. Casting numbers could be used for multiple engine displacements during the same model year. The same block could appear in both 2-bolt and 4-bolt main configurations, depending on application. Multiple casting numbers were sometimes used for the same application in a model year.

 

Block Casting Numbers
Bore 1964 1965 1966 1967 1968 1969 1970
L6  3.875″  3877178
3921968
 3921968  3921968
283  3.875″ 3834810
3849852
3834810
3849852
3849852 3896944
307 3.875″ 3914636
327 4.0″ 3782870 3782870
3858180
3858180 3892657
3903352
3914660
3914678
3932386
3932388
3956618
3970010
350 4.0″ 3970010
396 4.094″ 3855961
3855962
3855961 3902406
3916323
3916323
3935440
3935440
3955272
400 4.125″ 3951509
3951511
409 4.3125″ 3844422 3844422 *
3857656
427 & 454 4.251″ 3869942 3904351 3916321
3935439
3935439
3955270
3963512
3963512
* – see note below

 

  • A 3844422 block has been found from a early 65 409/400 motor stamped with the JA engine suffix and Wilmington, DE partial vin.

 

Block Casting Date

The block casting date was either cast on the top, back of the block or on the passenger’s side between the freeze plugs.  The 64 and 65 409 blocks, used a date code that stated the day of the year the block was cast.  For example, 365 would be the last day of the year, December 31st and 1 would be January 1st. It is located on the top, rear of the block on the passenger’s side.

All other blocks used a Month, Day, Year format.  The letter is the month the block was cast.  A is January, B February, C March, I September, L December. etc.  That is followed by the day of the month it was cast and the year. E 13 5 would be May 13th, 1965.  On small blocks, the casting date was located next to the casting number.  On big blocks, it was located between the freeze plugs on the passenger’s side.

The casting date is usually less than 30 days before the engine assembly date.  However, some can be several months earlier or longer.  Those cases are rare.


Transmission Codes

The transmission code consisted of the type of transmission and the date it was assembled.  The different kinds of codes used will be detailed below.  Pretty much all transmissions used the same format for the code except the Turbo 400.

For all transmissions except the TH400, these are the transmission type codes used.

Powerglide and TH350 code location. Passenger's side of the transmission oil pan.

Powerglide and TH350 code location. Passenger’s side of the transmission oil pan.

Automatic
C: Cleveland Powerglide
T: Toledo Powerglide
E: McKinnon Powerglide
B: Cleveland TH350
Y: Toledo TH350
Manual
S: Saginaw 3-speed
K: McKinnon 3-speed

Saginaw 3-speed and 4-speed code location. Driver's side of case below side cover.

Saginaw 3-speed and 4-speed code location. Driver’s side of case below side cover.

P: Muncie 4-speed
R: Saginaw 4-speed
W: H.D. Warner 3-speed
H: H.D. Muncie 3-speed (69 only)

Examples for 1964-1966 transmission code format:
C1210   Cleveland Powerglide assembled on December 10th
P0301   Muncie 4-speed assembled on March 1st

 

 

trans_4J267988_P0413

1964 Muncie 4-speed code location. Driver’s side of main case on machined surface for side cover, bottom right. Note: Partial VIN number from Janesville, WI plant.

Starting in 1967, the transmission code date format changed.  Following the transmission type, was the model year, month and day of the month.  The letters used for the month were not the same exact as those used in the engine casting date.

A – Jan, B – Feb, C – Mar, D – Apr, E – May, H – June, K – July,
M – Aug, P – Sep, R – Oct, S – Nov, T – Dec.

Examples for 1967-1970 transmission date code format:
Y9E10   1969 Toledo TH350 assembled on May 10th
P8T03   1968 Muncie 4-speed assembled on December 3rd

1965-1969 Muncie 4-speed code location. Drivers side, rear edge of the main case.

1965 and up Muncie 4-speed code location. Passenger’s side, rear edge of the main case.

Turbo 400 transmission code format

The Turbo 400 automatic transmission has the application and date codes stamped on a metal tag riveted to the passenger’s side of the transmission case.  The tag has several codes on it, which consisted of the full transmission code with Julian date code, application code, model year and serial number of the transmission.  This full transmission code will be found on your Protect-O-Plate if it still with your car.  The actual application code that would be found on the broadcast sheet and that is also on the tag starts with a C for Chevrolet but the C is omitted in the transmission code.  For example, the application code may be CB but in the transmission code itself, only a B will be used.

The following is a list of TH400 application codes used only on the full-size Chevrolets.

CA 396 engine (also 350 engine in 1969)
CB 427 engine (L36)
CD 327 engine
CF 427 engine (LS1 with 2.29:1 axle)
CG 396 engine (with 2.29:1 axle)
CH 427 engine (L36 with 2.29:1 axle)
CM 307 engine
CQ 427 engine (LS1)
CY 427 engine (L72)

The Julian date in the transmission code started at 1 for January 1st of the start of that model year and continued past 365 until the end of production.  For example, transmissions built early in the model year in August and September would have a date code in the 200’s where as those built after January 1st would start from 366.  Transmissions assembled in July would have a date in the 500’s.

67A509  67 TH400 for use with 396 engine, assembled on May 24th
69B350  69 TH400 for use with 427 (L36) engine assembled on December 16th

 


Rear Axle Numbers

The rear axle is final component of the drivetrain to be covered on this page.  What can be found on the axle housing is the stamped axle code with assembly date, housing casting number and date housing was cast.  In 1964, the axle code was stamped on the front, right side of the differential carrier housing.  Starting in 1965, the axle code and date are stamped on the front of the axle tube on the passenger’s side.  The casting number is located on the front of the carrier on the bottom right corner.  The casting date is on the rear of the carrier, towards the top on the driver’s side.  The rear axle casting date uses the fame format as the engine casting date.

axle_8L163442_date

The assembly code consists of the application code, assembly date and assembly plant.  Axles were assembled at either Buffalo (code B) or Detroit Gear and Axle (code G).  One exception was in 1964 when the first letter of the application code was the plant. (A – Detroit, B – Buffalo).  On positraction axles, a letter for manufacturer of the posi unit will appear under the assembly code.  It will be a D for Dana, E for Eaton or W for Warner.

Sample 1964 axle code: AB1202
BB 3.36 non posi assembled at Detroit
1202 assembled December 2nd

A sample 1965-1969 rear axle code would look like DH1020B which decodes to the following:
DH: 3.31 12 bolt rear axle with positraction
1020: Assembled October 20th
B: Buffalo axle plant

The following will be a table of application codes for the axles used in the full-size Chevrolets.  Prior to the 10 bolt/12 bolt rear axles that came out in 1965, the axle housing was the same for all ratios.  The gear set was installed in a carrier, also referred to as a “pumpkin” that could removed from the front side of the axle assembly as a complete unit.  It was possible to change gear sets simply by swapping the pumpkin.  The carrier assembly came in both positraction and non-positraction versions. SW is station wagon.

 

1964
Code Ratio Type Other
AA BA 3.55 N
AB BB 3.36 N
AC BC 3.70 N Overdrive
AD BD 3.36 N Taxi
AE 3.55 N J65
AF 3.70 N J65
AG 3.36 N J65
AH BH 3.70 Y
AJ 3.08 N J65
AK BK 3.55 Y
AL 4.11 N
AM BM 3.36 Y
AN 3.55 Y J65
AP 3.70 Y J65
AQ 3.36 Y J65
AR 3.08 Y J65
AS 4.56 Y
AT 4.11 Y J65
AU 4.56 Y J65
AV 3.08 N J65, HD Chassis
AW BW 3.08 N
AX BX 3.08 Y
AY 3.36 N J65, HD Chassis
AZ 3.55 N J65, HD Chassis

 


1965 1966 1967 1968 1969
Code Ratio Size Type Other Ratio Size Type Other Ratio Size Type Other Ratio Size Type Other Ratio Size Type Other
DA 3.08 10 N 3.08 10 N 3.08 10 N 3.08 10 N 3.08 10 N
DB 3.36 10 N 3.36 10 N 3.36 10 N 3.36 10 N 3.36 10 N
DC 3.55 12 N 3.55 12 N 3.55 12 N 3.55 12 N 3.55 12 N
DD 3.31 12 N 3.31 12 N 3.31 12 N 3.31 12 N 3.31 12 N
DE 3.31 12 N H.D. Chassis 3.31 12 N H.D. Chassis 3.31 12 N H.D. Chassis 3.31 12 N H.D. Chassis 3.31 12 N H.D. Chassis
DF 3.07 12 P 3.07 12 P 3.07 12 P 3.07 12 P 3.07 12 P
DG 3.08 10 P 3.08 10 P 3.08 10 P 3.08 10 P 3.08 10 P
DH 3.31 12 P 3.31 12 P 3.31 12 P 3.31 12 P 3.31 12 P
DI 3.36 10 P 3.36 10 P 3.36 10 P 3.36 10 P 3.36 10 P
DJ 3.55 10 P 3.55 10 P 3.36 10 P 3.36 10 P 3.36 10 P
DK 3.55 12 P 3.55 12 P 3.55 12 P 3.55 12 P 3.55 12 P
DL 3.70 10 P 3.70 10 P 3.70 10 P 3.70 10 P 3.70 10 P
DM 3.73 12 P 3.73 12 P 3.73 12 P 3.73 12 P 3.73 12 P
DN 4.10 12 P 4.10 12 P 4.10 12 P 4.10 12 P 4.10 12 P
DO 4.56 12 P 4.56 12 P 4.56 12 P 4.56 12 P 4.56 12 P
DP 4.88 12 P 4.88 12 P 4.88 12 P 4.88 12 P 4.88 12 P
DQ 3.55 10 N 3.55 10 N 3.55 10 N 3.55 10 N 3.55 10 N
DR 3.07 12 N J65 3.07 12 N J65 3.07 12 N J65
DS 3.07 12 P J65 3.07 12 P J65 3.07 12 P J65 2.56 12? N
DT 3.08 10 N J65 3.08 10 N J65 2.56 12? P
DU 3.08 10 P J65 3.08 10 P J65 2.73 12? N
DV 3.31 12 N J65 3.31 12 N J65 3.31 12 N J65 2.73 12? P
DW 3.31 12 P J65 3.31 12 P J65 3.31 12 P J65 3.08 10 N
DX 3.36 10 N J65 3.36 10 N J65 2.73 10 P 2.73 10 P
DY 3.36 10 P J65 3.36 10 P J65 2.73 10 P 2.73 10 P
DZ 3.55 10 N J65 3.55 10 N J65 2.73 10 N 2.73 10 N
EA 3.55 10 P J65 3.55 10 P J65 2.56 12 N
EB 3.55 12 N J65 3.55 12 N J65 3.55 12 N J65 2.29 10 N
EC 3.55 12 P J65 3.55 12 P J65 3.55 12 P J65 2.29 10 P
ED 3.70 10 N J65 3.70 10 N J65 2.56 12 P
EE 3.70 10 P J65 3.70 10 P J65
EF 3.73 12 N J65 3.73 12 N J65 3:73 12 N J65 2.56 10? N
EG 3.73 12 P J65 3.73 12 P J65 3:73 12 P J65 2.56 10? P
EH 4.10 12 N J65 4.10 12 N J65 4.10 12 N J65 3.08 10 P
EI 4.56 12 N J65 4.56 12 N J65 4.56 12 N J65 3.36 10 N
EJ 4.88 12 N J65 4.88 12 N J65 4.88 12 N J65 3.36 10 P
EK 3.70 10 N Overdrive 3.70 10 N Overdrive 3:70 10 N Overdrive 3.70 10 N Overdrive
EL 3.73 12 N Overdrive 3.73 12 N Overdrive 3:73 12 N Overdrive 3.73 12 N 3.73 12 N
EM 3.07 12 N 3.07 12 N 3:07 12 N 3.07 12 N 3.07 12 N F40
EN 3.07 12 N L30&M35 3.07 12 N 327&M35 3:07 12 N 327&M35 3.07 12 N 3.07 12 N Police
EO 3.55 12 N H.D. Chassis 3.55 12 N H.D. Chassis 3:07 12 N H.D. Chassis 3.55 12 N 3.55 12 N
EP 2.73 12 N M40 2.73 12 N M40 2.73 12 N M40 2.73 12 N
EQ 2.73 12 P 2.73 12 P 2.73 12 P 2.73 12 P
ER 2.73 12 N J65 2.73 12 N J65&M40 2.73 12 N J65 3.55 ? N
ES 2.73 12 P J65 2.73 12 P J65&M40 2.73 12 P J65
ET 2.73 ? ? L30/M40
EU 3.36 10 N 327, 4 link 3.36 10 N 327, 4 link 3.36 10 N 327, 4 link 3.36 10 N 4 link
EW 3.70 10 P SW&J65, 4 link
EX 3.70 10 N SW w/OD, 4 link 3.70 10 N OD, 4 link 3.70 10 N
EY 3.70 10 P 4 link 3.70 10 P 4 link 3.70 10 P 4 link
EZ 3.70 10 N J65, 4 link 3.70 10 N J65, 4 link 2.73 10 N 2.73 10 N
FD 2.29 12 N
FE 2.29 12 P
FF 3.55 ? P
FS ? ? ? 327/M38
FT 2.56 10 N 2.56 10 N
FU 2.56 10? P 2.56 10? P
FV 2.56 12 P 2.56 12 P
FW 2.56 12 N 2.56 12 N
FX 2.56 12 P 2.56 12 P
GA 3.07 12 N M40&C60 3:07 12 N 3.07 12 N
GB 2.73 12 N J65
GC 2.73 12 P J65
GD 3.07 12 N Taxi
GE 3.31 12 N Taxi
GF 3.07 12 P M40 3.07 12 P 3.07 12 P
GG 3.07 12 N J65&M40 2.73 12 N J65
GH 3.31 12 P HD Brakes 3.31 12 P HD Brakes
GI 12 3.31 N M40&C60 3.31 12 N 3.31 12 N
GJ 3.31 12 P 3.31 12 P 3.31 12 P
GK 2.73 12 N 2.73 12 N 2.73 12 N
GL 3.07 12 N J65 3.07 12 N J65
GM 2.73 12 P 2.73 12 P 2.73 12 P
GN 3.31 12 N J65 3.31 12 N J65
GO 3.31 12 P J65 3.31 12 P J65
GP 3.55 10 N 3.55 10 N 3.55 10 N 3.55 10 N
GQ 3.08 10 N L30&M35, 4 link 3.08 10 N 4 link 3.08 10 N 4 link 3.08 10 N 4 link
GR 3.08 10 P 4 link 3.08 10 P 4 link 3.08 10 P 4 link 3.08 10 P 4 link
GS 3.08 10 N J65, 4 link 3.07 12 N 3.07 12 N
GT 3.08 10 P J65, 4 link 3.07 12 P HD Brakes 3.07 12 P HD Brakes
GU 3.36 10 P 4 link 3.36 10 P 4 link 3.36 10 P 4 link 3.36 10 P 4 link
GV 3.36 10 N J65, 4 link 3.36 10 N J65, 4 link 3.55 12 P HD Brakes 3.55 12 P
GW 3.36 10 P J65, 4 link 3.36 10 P J65, 4 link 3.07 12 P HD Brakes 3.07 12 P HD Brakes
GX 3.55 10 P SW, 4 link 3.55 10 P 4 link 3.55 10 P 4 link 3.55 10 P 4 link
GY 3.55 10 N J65, 4 link 3.55 10 N J65, 4 link
GZ 3.55 10 P? J65?, 4 link 3.55 10 P? J65?, 4 link
AAW ?? 12 N Police w/OD
BBG 3.07 12 P Police
CCA ?? 12? ? Police?
DDB 3.?? 12 ? Police
DDS ?? 12 ? Police


1970 Rear Axle Codes

 

1970
Code Ratio Size Type Other
CDA 3.08 10 N
CDC 3.55 12 N
CDD 3.31 12 N
CDE 3.31 12 N
CDF 3.07 12 P
CDG 3.08 10 P
CDH 3.31 12 P
CDK 3.55 12 P
CDR 2.73 12 P Heavy Duty, Police?
CDX 2.73 10 P
CDZ 2.73 10 N
CEA 2.56 10 N
CEC 2.29 12 N
CED 2.56 10 P
CEK 2.73 12 N Heavy Duty, Police?
CEM 3.07 12 N
CEN 3.07 12 N
CES 3.08 10 P Heavy Duty, Police?
CET 3.08 10 P
CEU 3.36 10 N
CEV 3.36 10 P Heavy Duty, Police?
CEW 3.36 10 P
CEZ 2.73 10 N
CE3 2.73 10 N
CFW 2.56 12? N
CFX 2.56 12? P
CGH 3.31 12 P
CGK 2.73 12 N
CGM 2.73 12 P
CGQ 3.08 10 N
CGR 3.08 10 P
CGU 3.36 10 P
CGW 3.07 12 P
CLJ 2.56 10 P
CLK 2.73 10 P
CLN 3.07 12 P
CMY 2.56 10 N
CNA 2.73 10 N
CND 3.07 12 N
CWK 3.07 12 N
CWO 2.29 12 N
CWP 3.07 12 P
CWT 3.31 12 P Heavy Dity, Police?
CWU 3.31 12 P
CWY 3.31 12 N
CWZ 3.31 12 P
CXA 3.55 12? N
CXB 3.55 12? P

 

10 comments for “Drivetrain Decoding

  1. jarmo
    October 21, 2016 at 4:37 am

    Hello, I just looked the code of my Impala but what engine this really is?
    F0923R Can it be 327/?

    • admin
      December 2, 2016 at 3:33 pm

      Yes, 327/250 with manual transmission

  2. Pete
    October 26, 2016 at 12:28 pm

    I have seen on several other sites that the suffix LI is a 335 hp, 427. Does this list apply to Impala’s or is there a discrepancy?

    • admin
      December 2, 2016 at 3:34 pm

      Any site that says LI is 335hp is incorrect

  3. Steve Foster
    July 18, 2017 at 10:07 am

    my code on a 66 impala is DB0504G your chart for 1966 says Posi for that one year only is that correct ?

    • admin
      July 20, 2017 at 9:05 pm

      That was a typo. Thanks for catching it. I corrected it.

  4. Gerald McCracken
    July 23, 2017 at 11:05 am

    I have a 1966 chevy Biscayne, L72 that I order new.
    It has a F & SO-COPO number on 5th line on cowl tag. These numbers match the tag I found under the rear seat under the F & SO-COPO position?
    I know its special ordered, though I don’t know what the numbers mean?
    Does it make it a COPO??.

    • admin
      July 25, 2017 at 11:39 am

      That 310 number happens to appear under the F&SO section but a number appears there on all cars.

  5. Greg
    November 24, 2017 at 11:58 pm

    I have a 1967 Impala SS with FC429S stamped on front passenger side of the block. Can anyone tell me what this is telling me ?
    Thanks

    • admin
      December 10, 2017 at 10:52 pm

      F0429S is a pre 65 327 engine out of a fullsize car

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