Independent · Source-led · American performance history Issue 01 · 1951–2023
American Muscle Car Facts

Showroom arguments.
Race-bred answers.

Scheme guide · 1954–1957

Cadillac serial (engine) number, 1954–1957

What each character of a 1954–1957 Cadillac VIN means, with the factory or regulatory source for every code.

4 sources · 20 sourced codes · decode a VIN

Peach-colored cover of the 1955 Cadillac Data Book with a painted black 1955 Cadillac seen from the front, its V-and-crest emblem and the words 1955 Data Book
Cover of the 1955 Cadillac Data Book, showing the front of a 1955 Cadillac

Serials of this scheme appear in more than one length (the factory did not always print leading zeros), so 10-character numbers and 9-character numbers all decode with the codes below.

Character by character

PositionsFieldHow it is read
1–2 Model year See the code table below
3–4 Series See the code table below
5–10 Sequence Production sequence number

Where to find it: The serial is the engine number: flat machined boss at the upper right corner of the front face of the right-hand cylinder block; also on the right frame side bar behind the engine support bracket, and a lubrication plate on the left front body (or door lock) pillar (1954 Shop Manual p. 1-1; 1956 p. 1-1; 1957 p. 1-3).

Model year codes

CodeMeaningApplies toSource
54 1954 all 1954 Cadillac Shop Manual, Section 1 General Information, p. 1-1 (ManualsLib p. 5), Identification
55 1955 all 1955 Cadillac data book (GM Heritage vehicle information kit), License Data, PDF image 244, License Data
56 1956 all 1956 Cadillac Shop Manual, Section 1 General Information, p. 1-1 (OCMP image 5), Model Identification
57 1957 all 1957 Cadillac Shop Manual, Section 1 General Information, p. 1-1 (OCMP image 5)

Series codes

CodeMeaningApplies toSource
60 Series 60 Special (60S) model year 1954 1954 Cadillac Shop Manual, Section 1 General Information, p. 1-4 (ManualsLib p. 8), Models Included, Starting Engine No. column
62 Series 62 model year 1954 1954 Cadillac Shop Manual, Section 1 General Information, p. 1-4 (ManualsLib p. 8), Models Included, Starting Engine No. column
75 Series 75 model year 1954 1954 Cadillac Shop Manual, Section 1 General Information, p. 1-4 (ManualsLib p. 8), Models Included, Starting Engine No. column
86 Series 86 commercial chassis model year 1954 1954 Cadillac Shop Manual, Section 1 General Information, p. 1-4 (ManualsLib p. 8), Models Included, Starting Engine No. column
60 Series 60 Special (60S) model year 1955 1955 Cadillac data book (GM Heritage vehicle information kit), License Data, PDF image 244, License Data, Beginning Engine Numbers
62 Series 62 model year 1955 1955 Cadillac data book (GM Heritage vehicle information kit), License Data, PDF image 244, License Data, Beginning Engine Numbers
75 Series 75 model year 1955 1955 Cadillac data book (GM Heritage vehicle information kit), License Data, PDF image 244, License Data, Beginning Engine Numbers
86 Series 86 commercial chassis model year 1955 1955 Cadillac data book (GM Heritage vehicle information kit), License Data, PDF image 244, License Data, Beginning Engine Numbers
60 Series 60 Special (60S) model year 1956 1956 Cadillac Shop Manual, Section 1 General Information, p. 1-3 (OCMP image 7), Models Included, Starting Engine No. column
62 Series 62 model year 1956 1956 Cadillac Shop Manual, Section 1 General Information, p. 1-3 (OCMP image 7), Models Included, Starting Engine No. column
75 Series 75 model year 1956 1956 Cadillac Shop Manual, Section 1 General Information, p. 1-3 (OCMP image 7), Models Included, Starting Engine No. column
86 Series 86 commercial chassis model year 1956 1956 Cadillac Shop Manual, Section 1 General Information, p. 1-3 (OCMP image 7), Models Included, Starting Engine No. column
62 Series 62 model year 1957 1957 Cadillac Shop Manual, Section 1 General Information, p. 1-3 (OCMP image 7), Accessory Designation table, Series column
60 Series 60 (Sixty Special) model year 1957 1957 Cadillac Shop Manual, Section 1 General Information, p. 1-3 (OCMP image 7), Accessory Designation table, Series column
75 Series 75 model year 1957 1957 Cadillac Shop Manual, Section 1 General Information, p. 1-3 (OCMP image 7), Accessory Designation table, Series column
86 Series 86 commercial chassis model year 1957 1957 Cadillac Shop Manual, Section 1 General Information, p. 1-3 (OCMP image 7), Accessory Designation table, Series column

Cautions for this scheme

  • A decode reads what Cadillac's own shop manuals and data books say. It does not prove the car is original.
  • The number shows model year and series only; there is no plant or body-style code, and the sequence is the order of completion in final assembly.
  • Starting numbers are printed with five sequence digits (e.g. 546200001), so early cars have nine-digit numbers (decoded by gm-cadillac-1954-1957-short).

Where the sources disagree

  • {"code":"556200000","field":"sequence start","modelYears":{"from":1954,"to":1956},"claims":[{"claim":"1955 data book License Data gives beginning engine numbers ending 000000 (e.g. 556200000).","sources":[{"id":"vin-gm-db-1955-cadillac","locator":"PDF image 244, License Data"}]},{"claim":"1954 and 1956 shop manuals give starting engine numbers ending 000001 (546200001, 566200001).","sources":[{"id":"vin-gm-sm-1954-cadillac","locator":"p. 1-4 (ManualsLib p. 8)"},{"id":"vin-gm-sm-1956-cadillac","locator":"p. 1-3 (OCMP image 7)"}]}],"resolution":"Not a same-year conflict (no 1955 shop manual was read). The data book may state a \u0022beginning\u0022 value one below the first car. Treat 1955 sequence as numeric; do not reject 5562000001-style first cars; prefer a 1955 shop manual if found."}