Factory Stage1 Identification

This page starts with one thought: never say never when it comes to these cars. So much information has come to light about these cars in recent years and the information contained in this page is believed to be as accurate as possible. If someone has a question, update, or correction to any information contained on this webpage, please E-Mail Me: marco@stage1registry.com.

This webpage is a community effort, a 'knowledge dump', from many people who were willing to share their time and knowledge so we can all be more educated about these cars. Hopefully the information contained on this webpage will help you document your Buick GS. This webpage will be updated with any additional information or corrections as needed.

Disclaimer:

People have been known to fake Stage 1's by restamping/manipulating drivetrain components. In addition to the information listed here, there are additional ways to determine authenticity (ie - matching #s) such as date codes. Anyone doing research should try to contact 'those in the know' for help with that degree of documentation - Thank You!


Paperwork
'Official' Buick Documentation (paperwork) is the most definitive way to determine if a specific GS came from the factory with the Stage1 option. This includes Window Stickers, Build Sheets, Protect-O-Plates, Body Order - Production Final sheets, import sheets (cars sent to Canada) and IBM punch cards (originally contained in the glove box). The VIN on 1972-1974 model year cars also depicts the Stage1 engine option.

There is 'third party documentation' available from the Buick archives (Sloan Museum) for the first half of the 1970 model year (up to VIN 193xxx) and from 1972 through 1974.

The GS Historical Society can document the second half of the 1970 model year. Wayne Roberts is the person to contact at 248-879-2113.

Unfortunately, there is no 'third party documentation' available for the 1969 and 1971 model years.

NOTE: - I have seen many errors stamped on 1971 P-O-Ps that didn't match other pieces of documentation, and in some cases, the P-O-P didn't match itself. An example is a 1971 car which had a TB motor code (350) and an OW transmission code (TH400). Buick was not in the practice to put a TH400 behind a small block. GM had a 68-day strike (9/15/1970 - 11/20/1970) and I suspect more errors may have occurred on the 71 model year cars due to this strike. You can read about the GM strike
HERE if you wish.

Many cars didn't get build sheets at the assembly plant (including mine), and some that did actually received a buildsheet with a different VIN. Popular places to find a build sheet (if you're fortunate enough) - on top of the gas tank, inside the door panel (usually driver's side, but never say never), under the carpet (front or rear), rolled up under the dash, in the windshield pillar, or under the seats.

On top of the gas tank could possibly be the Production Order Body - Final sheet (Flint build only), or GMAD Build Sheets (all other plants) which will prove the authenticity of a Stage1 GS. If you are fortunate enough to find a POBF sheet on your Buick, Duane Heckman offers a decoding service. He can be reached at his website - Classic Car Interiors.

Different Types of Buick Build Sheets
POBF sheet (1969-1971 Flint built)
Please click to enlarge
'Other' (GMAD) Build Sheet
Please click to enlarge
Important Numbers At A Quick Glance - 1969-1974

Year Engine Block Engine Code Head Casting TH400 Code Carburetor Distributor Rear
1969@ 1383790 RS 1231109 BB 7029246 1111962 'OO' - 3.42 (A/C)
'ON' - 3.64 (no A/C)
1970@ 1231738 SS 1231786
1240149# / 1240150#
BB 7040246 1112016 'OO' - 3.42 (A/C)
'ON' - 3.64 (no A/C)
1971& 1231738 / 1238861 TS 1237661
1240145# / 1240149#
OW / BB% 7041242 1112016 'LWB' - 3.42
A/C and non-A/C
1972& 1238861 / 1241735 WS 1238148 / 1242445
1242449# / 1242455#
BB 7042242 (49 State)
7042942 (California)
1112016 'LW' - 3.42
A/C and non-A/C
1973& 1241735 XS 1241860 BB 7043242 1112087?? 'CJ' - 3.42
A/C and non-A/C
1974& 1241735 ZS 1241860 BB 7044242 1112521 1974 rear info needed
@ - According to Buick's official records (Daily Car Reports), all factory 1969-1970 stage1 Gran Sports built in Flint MI (plant code 'H').
# - Correct year replacement head casting
& - Stage1 Gran Sport coupes assembled in one of three plants - Flint MI (code 'H'), Framingham MA (code 'G'), and Fremont CA (code 'Z').
      All stage1 convertibles (1971-1972) assembled in Flint MI (code 'H') only.
% - Early 1971 model year cars will likely have an OW transmission, while later model year cars will likely have a BB transmission.

Location of Engine / Transmission Stampings
If the GS has no paperwork, and 3rd party documentation is unavailable, the original drivetrain can also prove factory Stage1 option.

1969-1970 Motor Identification (E1)
1971-1974 Motor Identification (E2)
1975-1976 Motor Identification (E3)


Transmission VIN Identification (T1)
Transmission Code Identification (T2)
BB Trans Tag
Transmission Code Identification (T3)
OW Trans Tag - 1971 Only


Common Stage1 Features - 1969-1974
1969
Here are the specific components to the 1969 stage1 package. Please click the picture to enlarge.

VIN
All 1969 factory Stage1 Gran Sports (1256 coupes/212 convertibles) were GS400s built in Flint Michigan. That means that the VIN must start with either 446379H for a coupe or 446679H for a convertible.

Visual Identification
The hood has two Stage1 emblems, in addition to a '400-Stage1' sticker on chrome valve covers. Some air cleaner lids were chrome, while others were black. The chrome air cleaner lid was a 'dress-up' option available to any GS model.

1969 Engine Identification 1969 Transmission Identification
1970
Here are the specific components to the 1970 stage1 package. Please click the picture to enlarge.

VIN
All 1970 factory Stage1 Gran Sports (2865 coupes (includes 400 GSXs)/232 convertibles) were GS455s built in Flint Michigan. That means that the VIN must start with either 446370H for a coupe or 446670H for a convertible.

Visual Identification
Each fender has a 'Stage 1' emblem under the 'GS' emblem, in addition to a stage 1 decal on top of a black air cleaner lid. The valve covers are chrome, in addition to the nuts and spark plug wire retaining posts. There should be a 7-blade fan (Heavy Duty cooling).

1970 Engine Identification 1970 Transmission Identification
1971
VIN
In 1971, Buick changed the attributes of the VIN in that the VIN does not indicate the engine size. The VIN will only tell you if it's a Gran Sport model, and does not indicate if the car was built with a 350, 455, or 455 stage1 motor. Visual Identification
Same as 1970 above.

1971 Engine Identification 1971 Transmission Identification
1972
VIN
Starting in 1972, the Buick changed the VIN coding again to identify the motor option. VIN alone can prove the car came from the factory with the stage1 option. If the 5th digit is a 'V', the car is a stage1. Visual Identification
Same as 1970 above.

1972 Engine Identification 1972 Transmission Identification
1973
VIN
VIN alone can prove the car came from the factory with the stage1 option. If the 5th digit is a 'V', the car is a stage1.

Interested in 1973 Stage1 facts and option production figures? Click here.

1974
VIN
VIN alone can prove the car came from the factory with the stage1 option. If the 5th digit is a 'V', the car is a stage1.


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- This page last updated 11:09 PM 8/19/2015