General InformationYear:1972Make: ChevroletSeries: ZModel: CorvetteEngine: 350ciHorsepower: 200Transmission: Four-Speed Turbo-Hydramatic 400Engine Code suffix: CKX
BlockCasting No. 3970010 or No. 3970014Main: Two-bolt
Cylinder HeadCasting No. 3973487X or No. 3998993Intake/Exhaust Valve Size: 1.94/1.50Combustion Chamber: 75.47
Intake Manifold (Cast-Iron)Casting No. 6263751Carb Type: 1x4-bbl Rochester
CarburetorRochester 4-bbl No. 7042202Could be Rochester or Carter built
Exhaust ManifoldsCasting (Left-hand) No. 3932461Casting (Right-hand) No. 3989036
DistributorStamping No. 1112050Engine/HP: 350/200hpHousing: Cast-iron external adjustmentPoint: Single/EMCNotes: Tach drive, vacuum advance
Alternator1100950, 42-amp, 350 std.
TransmissionThree-Speed Turbo-Hydramatic 400Maincase: AluminumExtension Housing: AluminumGear RatiosDrive: 2.48:1, 1.48:1, 1.00:1Low 2: 2.48:1Low 1: 2.48:1Reverse: 2.08:1Maincase Casting No. UnknownSpecial Information: The Turbo 400 was a carryover from 1971
'72 Rear AxlesAll '72 Corvette rear axles are stamped with an alphanumeric production code. The eight-digit code contains the axle-code prefix, manufacturing plant code, a date code, the build shift code, and the Posi-traction source (if applicable).
On the '72 Corvette IRS rear suspension, the differential code is stamped on the bottom of the differential carrier housing just forward of the rearend cover. The axle code reads from left to right. The two-letter prefix designates the gear ratio and any other specific information about the axle. The third digit is the plant code. The next three numbers designate the actual day of the year this axle was built (001-365). The seventh digit represents the shift the axle was manufactured on. The last character letter is the Posi-traction source. If a space or no letter follows the shift code, the axle did not originally come equipped with a Posi-traction axle.
Plant Codes:* B = Buick* C = Buffalo* G = Detroit Gear & Axle* K = McKinnon Industries* M = Pontiac of Canada* O = Oldsmobile* P = Pontiac* W = Warren, MI
Posi-Traction Codes:* (-) = No Posi-traction* D = Dana Posi-traction differential* E = Eaton Posi-traction differential* W = Warner Motive Posi-traction carrier
Example: AA G 218 1 E* AA = Axle Prefix: 3.55:1 Corvette Posi-traction axle* G = Assembly Plant: Detroit Gear & Axle* 218 = Day of Year: August 6, 1972* 1 = Shift: First* E = Posi-traction Source: Eaton
’72 Corvette Rear-Axle Codes |
| Gear Ratio | Code |
| Posi 3.55:1 | AA |
| Posi 3.70:1 | AB |
| Posi 4.11:1 | AC |
| Posi 3.36:1 | AX |
| Posi 3.36:1 | LR |
From Corvette By The Numbers by Alan Colvin, published in 2002, used with permission of Robert Bentley Publishers.