Does anyone know where the build sheet can be found on an 81?
In the early 80s GM ceased using the traditional build sheet and replaced it with the Service Production Parts (SPI) label. This lists all of the vehicles equipment and you will find it affixed to the underside of the trunk lid. It is all in alpha numeric codes and lists all of the pertinant RPO information to the car.
Mike
I seem to remember that in the past GM put their build sheets under the rear seat.