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 Headlight 1970 – 1972 H5006
High Beam Headlight 1970 – 1972 H5001
Back Up Light 1970 – 1972 1156
Brake 1970 – 1972 1157
Dome Light 1971 194
1970 211-2
1972 212-2
Front Side Marker 1972 194
1970 194NA
1971 97
Front Turn Signal 1970 – 1972 1157
License Plate 1970 – 1972 97
Parking Light 1970 – 1972 1157
Rear Side Marker 1971 1157
1970, 1972 194
Rear Turn Signal 1970 – 1972 1157
Tail Light 1970 – 1972 1157
Courtesy 1971 194
1970, 1972 90
Engine Compartment Light 1972 1004
1970 89
Glove Box 1970, 1972 1893
Map Light 1971 194
1972 578
1970 89
Radio Display 1972 1893
Trunk 1971 194
1970, 1972 89
Low Beam Headlight 1968 – 1969 H5006
High Beam Headlight 1968 – 1969 H5001
Back Up Light 1968 – 1969 1156
Brake 1968 – 1969 1157
Dome Light 1968 1004
1969 211-2
Front Side Marker 1968 – 1969 194NA
Front Turn Signal 1968 – 1969 1157
License Plate 1968 – 1969 97
Parking Light 1968 – 1969 1157
Rear Side Marker 1968 – 1969 194
Rear Turn Signal 1968 – 1969 1157
Tail Light 1968 – 1969 1157
Courtesy 1968 – 1969 90
Engine Compartment Light 1968 – 1969 89
Glove Box 1968 – 1969 1893
Map Light 1968 – 1969 89
Trunk 1968 – 1969 89
Low Beam Headlight 1968 – 1969 H5006
High Beam Headlight 1968 – 1969 H5001
Back Up Light 1968 – 1969 1156
Brake 1968 – 1969 1157
Dome Light 1968 1004
1969 211-2
Front Side Marker 1968 – 1969 194NA
Front Turn Signal 1968 – 1969 1157
License Plate 1968 – 1969 97
Parking Light 1968 – 1969 1157
Rear Side Marker 1968 – 1969 194
Rear Turn Signal 1968 – 1969 1157
Tail Light 1968 – 1969 1157
Courtesy 1968 – 1969 90
Engine Compartment Light 1968 – 1969 89
Glove Box 1968 – 1969 1893
Map Light 1968 – 1969 89
Trunk 1968 – 1969 89
Low Beam Headlight 1970 – 1972 H5006
High Beam Headlight 1970 – 1972 H5001
Back Up Light 1970 – 1972 1156
Brake 1970 – 1972 1157
Dome Light 1971 194
1970 211-2
1972 212-2
Front Side Marker 1972 194
1970 194NA
1971 97
Front Turn Signal 1970 – 1972 1157
License Plate 1970 – 1972 97
Parking Light 1970 – 1972 1157
Rear Side Marker 1971 1157
1970, 1972 194
Rear Turn Signal 1970 – 1972 1157
Tail Light 1970 – 1972 1157
Courtesy 1971 194
1970, 1972 90
Engine Compartment Light 1972 1004
1970 89
Glove Box 1970, 1972 1893
Map Light 1971 194
1972 578
1970 89
Radio Display 1972 1893
Trunk 1971 194
1970, 1972 89