[retengw31]

I can help out a litle on Oldsmobiles built in Lansing plant from 1968-1973 when I was a process engineer on the final assembly line. Among many other things, VIN stamping on the frames was one of my responsibilities.

All the Olds cars built then were body/frame and the only hidden VIN stamps were on the top frame rails on the drivers side in two places. One was near the transmission crossmember and the other was behind the rear wheel. In each case, it was a 9 digit alphanumeric with the division (Olds was number 3), the year (8 for 68, etc.), the plant code (Lansing was M), and the 6 digit sequential number starting with 100000. This same number was hand stamped on the engine block and the transmission casing with a BFH. Only other place the VIN appeared in the car was on the VIN plate that was rivetted to the upper I/P and the blue sticker/label in the door jambs after 1970(I think).

I think that policy also applied to other GM divisions with body frame cars, not sure what they did on unibody and partial frame cars (like Camaro/Nova, etc.)