What’s a “V” Code?

by Greg Mross (last updated on 12/7/03)

In 1972, Oldsmobile used the 5th digit of the VIN to designate the engine used in the vehicle. In big block Cutlass applications, there were 3 codes, “U” for big block automatics, “V” for big block 4 speeds, and “X” for W-30’s. The following documents what made “V” codes different from other big blocks. Note that much of what is documented here also applies to W-30 4 speeds, but their VIN code does not designate what transmission was used.

Lets start with the obvious. All “V” code cars came with the L-75/M-20 4 speed combination. They also came with a 3.23 rear end (3.42 or 3.73 ratios were available only on W-30’s). Positraction was optional.

The engine was basically the same as those found in W-30 automatics and was rated at 270 HP, 20 HP more than automatics. The camshaft was the same as the W-30 automatics, and the Ga heads featured the larger 2.072 intake valves. There was also an oil deflector attached to the rear main bearing. The PCV valve was mounted to a fitting in the front of the intake manifold, not on the valve cover. Both valve covers (notched in the rear on all 455 Cutlasses) had air breathers that went to the air cleaner, like W-30’s with OAI. The air cleaner also has a larger inlet snorkel. The engine code decal on the oil filler tube is either UD or UE (w/ HD clutch). W-30’s are either UL or UN (w/ HD clutch). The Quadrajet carb had an anti-dieseling solenoid.

The transmission is a Muncie wide ratio M-20 with a fine spline input shaft. Really clean trannys should have a 1 inch high “WD” stenciled on the side. The last 8 digits of the VIN should be stamped on the transmission where the housings split apart. These cars originally had a complete backdrive linkage that went to the frame and then up to the steering column. This forced the transmission to be in reverse before the key could be removed from the ignition. This linkage was frequently removed and replaced with an aftermarket Hurst linkage. There was also a switch on the clutch pedal that would not allow the car to start unless the clutch pedal was depressed. The driveshaft tunnel was cut (apparently with a torch) for the hole for the shifter. The boot retainer was made of metal and was welded to the tunnel. Different carpeting was required with 4 speed cars and the shift lever was different depending on whether the car had a bench seat or buckets.

Other items specific to “V” code cars include a dual snorkel air cleaner (for cars that did not have factory OAI setups). This unit is Part # 6487337 / Code NH. (See the Air Cleaner Page.) They also have radiators without an oil cooler (for the automatic transmission) in one of the tanks, and an additional metal re-enforcement bracket that was attached to the bottom of the core support. The routing for the positive battery cable was also unique and ran along the intake manifold and the valve cover, and used a tube that routed the cable down the back of the cylinder head. The speedometer had no PRNDL printed on it (shared with floor shift automatics), and the steering column had no provision for the shift lever (also shared with floor shift automatics). Finally, it appears these cars were shipped with an engine break-in tag attached to the turn signal lever.

I hope I have covered everything. If not, please let us know. Thanks.

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