When doing replacement or upgrading on 1971 – 1977 GMC Sprint, the bulb size guide is necessary for you to take the reference.

1971 – 1977 GMC Sprint Bulb Size Guide
Low Beam Headlight	1976 – 1977	H4656
High Beam Headlight	1976 – 1977	H4651
High Beam and Low Beam Headlight	1971 – 1975	H6024
Back Up Light	1971 – 1977	1156
Brake	1971 – 1977	1157
Dome Light	1974 – 1977	561
	1971 – 1973	578
Front Side Marker	1971 – 1977	194
Front Turn Signal	1971 – 1977	1157
License Plate	1974 – 1977	168
	1971 – 1973	97
Parking Light	1971 – 1977	1157
Rear Side Marker	1971 – 1977	194
Rear Turn Signal	1971 – 1977	1157
Tail Light	1971 – 1977	1157
Courtesy	1971 – 1973	212-2
	1974 – 1977	89
Engine Compartment Light	1971 – 1977	1003
Glove Box	1974 – 1977	1893
	1971 – 1973	1895
Map Light	1974 – 1977	561
Radio Display	1971 – 1973	1816
	1974 – 1977	37