70 W31 Identification

[Stefano]

The W-31 engine code is not stamped on the engine. If it is then there is an issue. The only identifier stamped into an original W-31 engine ( unless it was an over the counter w-31) is the VIN dirivative. 3 -for Oldmobile division, M- for the lansing Michigan plant, where all W-machines we built. 0- for the model year and then six numbers which should match the last 6 digits of the VIN.

A regular Cutlass with its original engine would have the same info stamped into it. So no it will not identify a W-31 nor will it identify a 4 speed car.

Same holds true for a W-30 as well.