When doing replacement or upgrading on 1960 – 1966 GMC 1000 1500 2500 3000 3500 Series 2 4 headlamps with, the bulb size guide is necessary for you to take the reference.

1966 GMC 1000 Bulb Size Guide
Low Beam Headlight	1966	H5006
High Beam Headlight	1966	H5001
Brake	1966	1034
Dome Light	1966	211-2
Front Turn Signal	1966	1156
Parking Light	1966	67
Rear Turn Signal	1966	1156
Tail Light	1966	1157

1960 – 1965 GMC 1000 Series with 4 headlamps Bulb Size Guide
Low Beam Headlight	1960 – 1965	H5006
High Beam Headlight	1960 – 1965	H5001
Brake	1960 – 1965	1157
Dome Light	1960 – 1965	211-2
Parking Light	1960 – 1965	67
Tail Light	1960 – 1965	1157

1960 – 1965 GMC 1000 Series with 2 headlamps Bulb Size Guide
High Beam and Low Beam Headlight	1960 – 1965	6014
Brake	1960 – 1964	1034
	1965	1157
Dome Light	1960 – 1965	211-2
Parking Light	1960 – 1965	67
Tail Light	1960 – 1965	1157

1966 GMC 1500 Bulb Size Guide
Low Beam Headlight	1966	H5006
High Beam Headlight	1966	H5001
Brake	1966	1157
Dome Light	1966	211-2
Front Turn Signal	1966	1156
Parking Light	1966	67
Rear Turn Signal	1966	1156
Tail Light	1966	1157

1960 – 1965 GMC 1500 Series with 4 headlamps Bulb Size Guide
Low Beam Headlight	1960 – 1965	H5006
High Beam Headlight	1960 – 1965	H5001
Brake	1961, 1965	1034
	1960, 1962 – 1964	1157
Dome Light	1960 – 1965	211-2
Parking Light	1960 – 1965	67
Tail Light	1960 – 1965	1157

1960 – 1965 GMC 1500 Series with 2 headlamps Bulb Size Guide
High Beam and Low Beam Headlight	1960 – 1965	6014
Brake	1961, 1964 – 1965	1034
	1960, 1962 – 1963	1157
Dome Light	1960 – 1965	211-2
Parking Light	1960 – 1965	67
Tail Light	1960 – 1965	1157

1966 GMC 2500 Bulb Size Guide
Low Beam Headlight	1966	H5006
High Beam Headlight	1966	H5001
Brake	1966	1034
Dome Light	1966	211-2
Front Turn Signal	1966	1156
Parking Light	1966	67
Rear Turn Signal	1966	1156
Tail Light	1966	1157

1960 – 1965 GMC 2500 Series with 4 headlamps Bulb Size Guide
Low Beam Headlight	1960 – 1965	H5006
High Beam Headlight	1960 – 1965	H5001
Brake	1960, 1962	1034
	1961, 1963 – 1965	1157
Dome Light	1960 – 1965	211-2
Parking Light	1960 – 1965	67
Tail Light	1960 – 1965	1157

1960 – 1965 GMC 2500 Series with 2 headlamps Bulb Size Guide
High Beam and Low Beam Headlight	1960 – 1965	6014
Brake	1960 – 1962, 1965	1034
	1963 – 1964	1157
Dome Light	1960 – 1965	211-2
Parking Light	1960 – 1965	67
Tail Light	1960 – 1965	1157

1966 GMC 3000 Bulb Size Guide
Low Beam Headlight	1966	H5006
High Beam Headlight	1966	H5001
Brake	1966	1157
Dome Light	1966	211-2
Front Turn Signal	1966	1156
Parking Light	1966	67
Rear Turn Signal	1966	1156
Tail Light	1966	1157

1960 – 1965 GMC 3000 with 4 headlamps Bulb Size Guide
Low Beam Headlight	1960 – 1965	H5006
High Beam Headlight	1960 – 1965	H5001
Brake	1960	1034
	1961 – 1965	1157
Dome Light	1960 – 1965	211-2
Parking Light	1960 – 1965	67
Tail Light	1960 – 1965	1157

1960 – 1965 GMC 3000 with 2 headlamps Bulb Size Guide
High Beam and Low Beam Headlight	1960 – 1965	6014
Brake	1960 – 1962, 1964	1034
	1963, 1965	1157
Dome Light	1960 – 1965	211-2
Parking Light	1960 – 1965	67
Tail Light	1960 – 1965	1157

1966 GMC 3500 Bulb Size Guide
Low Beam Headlight	1966	H5006
High Beam Headlight	1966	H5001
Brake	1966	1034
Dome Light	1966	211-2
Front Turn Signal	1966	1156
Parking Light	1966	67
Rear Turn Signal	1966	1156
Tail Light	1966	1157

1960 – 1965 GMC 3500 with 4 headlamps Bulb Size Guide
Low Beam Headlight	1960 – 1965	H5006
High Beam Headlight	1960 – 1965	H5001
Brake	1960 – 1965	1157
Dome Light	1960 – 1965	211-2
Parking Light	1960 – 1965	67
Tail Light	1960 – 1965	1157

1960 – 1965 GMC 3500 with 2 headlamps Bulb Size Guide
High Beam and Low Beam Headlight	1960 – 1965	6014
Brake	1961 – 1963	1034
	1960, 1964 – 1965	1157
Dome Light	1960 – 1965	211-2
Parking Light	1960 – 1965	67
Tail Light	1960 – 1965	1157