When doing replacement or upgrading on 1968 – 1972 Buick GS 350 400 455, the bulb size guide is necessary for you to take the reference.
Jump to corresponding car model with the catalog bellow.

Low Beam Headlight1970 – 1972 H5006
High Beam Headlight1970 – 1972 H5001
Back Up Light1970 – 1972 1156
Brake1970 – 1972 1157
Dome Light1971 194
1970 211-2
1972 212-2
Front Side Marker1972 194
1970 194NA
1971 97
Front Turn Signal1970 – 1972 1157
License Plate1970 – 1972 97
Parking Light1970 – 1972 1157
Rear Side Marker1971 1157
1970, 1972 194
Rear Turn Signal1970 – 1972 1157
Tail Light1970 – 1972 1157
Courtesy1971 194
1970, 1972 90
Engine Compartment Light1972 1004
1970 89
Glove Box1970, 1972 1893
Map Light1971 194
1972 578
1970 89
Radio Display1972 1893
Trunk1971 194
1970, 1972 89
Low Beam Headlight1968 – 1969 H5006
High Beam Headlight1968 – 1969 H5001
Back Up Light1968 – 1969 1156
Brake1968 – 1969 1157
Dome Light1968 1004
1969 211-2
Front Side Marker1968 – 1969 194NA
Front Turn Signal1968 – 1969 1157
License Plate1968 – 1969 97
Parking Light1968 – 1969 1157
Rear Side Marker1968 – 1969 194
Rear Turn Signal1968 – 1969 1157
Tail Light1968 – 1969 1157
Courtesy1968 – 1969 90
Engine Compartment Light1968 – 1969 89
Glove Box1968 – 1969 1893
Map Light1968 – 1969 89
Trunk1968 – 1969 89
Low Beam Headlight1968 – 1969 H5006
High Beam Headlight1968 – 1969 H5001
Back Up Light1968 – 1969 1156
Brake1968 – 1969 1157
Dome Light1968 1004
1969 211-2
Front Side Marker1968 – 1969 194NA
Front Turn Signal1968 – 1969 1157
License Plate1968 – 1969 97
Parking Light1968 – 1969 1157
Rear Side Marker1968 – 1969 194
Rear Turn Signal1968 – 1969 1157
Tail Light1968 – 1969 1157
Courtesy1968 – 1969 90
Engine Compartment Light1968 – 1969 89
Glove Box1968 – 1969 1893
Map Light1968 – 1969 89
Trunk1968 – 1969 89
Low Beam Headlight1970 – 1972 H5006
High Beam Headlight1970 – 1972 H5001
Back Up Light1970 – 1972 1156
Brake1970 – 1972 1157
Dome Light1971 194
1970 211-2
1972 212-2
Front Side Marker1972 194
1970 194NA
1971 97
Front Turn Signal1970 – 1972 1157
License Plate1970 – 1972 97
Parking Light1970 – 1972 1157
Rear Side Marker1971 1157
1970, 1972 194
Rear Turn Signal1970 – 1972 1157
Tail Light1970 – 1972 1157
Courtesy1971 194
1970, 1972 90
Engine Compartment Light1972 1004
1970 89
Glove Box1970, 1972 1893
Map Light1971 194
1972 578
1970 89
Radio Display1972 1893
Trunk1971 194
1970, 1972 89