From the Wikipedia article on the Buick Electra:
“Although the overall design remained unchanged from 1985 to 1990, the Electra did undergo some noticeable changes. The first significant change came in 1987 when the Electra lineup lost the four-lamp “quad” headlights used in 1985?86 models in favor of composite one-piece headlights. In 1988 the Electra Park Avenue received what would later go on to become GM’s flagship engine, the 3800 V-6. The original 3.8 L V-6 was still offered in some Electra models through the 1988 model year and was designated by the VIN code 3, while Electras with the 3800 V-6 were designated by the VIN code C. In 1989 and 1990, GM added a new trim level to the Electra’s existing Limited, Park Avenue, and T-Type variants; the Park Avenue Ultra. The Ultra was essentially an upgrade to the Electra Park Avenue line and featured standard leather trim interior, a padded vinyl top, and a variety of otherwise minor changes. The Park Avenue Ultra did not gain much notoriety, however, until the following generation of Park Avenue, where the “Ultra” badge offered significantly more features.”
Oldsfan, you might check out Wikipedia, there’s an amazing amount of info on just about every car out there.