This part fits the following vehicles.
For Chevrolet:
Fits C10, C20, C30 (GAS):
1978-1979 L6 4.1L
1975-1979 L6 4.8L
1978-1979 V8 5.0L
1975-1979 V8 5.7L
1976-1979 V8 6.6L
1975-1979 V8 7.4L
Fits C10 Pickup, C20 Pickup, C30 Pickup:
1973-1974 L6 4.1L LPG
1973-1974 L6 4.1L GAS
1973-1974 L6 4.8L GAS
1974 L6 4.8L LPG
1973 V8 5.0L GAS
1973-1974 V8 5.7L GAS
1973 V8 5.7L LPG
1973-1974 V8 7.4L GAS
Fits K10, GAS:
1975-1979 L6 4.1L
1975-1976 L6 4.8L
1979 L6 4.8L
1977-1979 V8 5.0L
1975-1979 V8 5.7L
1975-1979 V8 6.6L
1979 V8 7.4L
1976 V8 7.4L
Fits K20 GAS:
1978-1979 L6 4.1L
1975-1976 L6 4.1L
1975-1979 L6 4.8L
1977-1978 V8 5.0L
1975-1979 V8 5.7L
1975-1979 V8 6.6L
1976-1978 V8 7.4L
Fits K30 GAS:
1977-1979 L6 4.8L
1977-1979 V8 5.7L
1977-1979 V8 6.6L
1977 V8 7.4L
Fits K10 Pickup, K20 Pickup,K30 Pickup:
1973-1974 L6 4.1L LPG
1973-1974 L6 4.1L GAS
1973-1974 L6 4.8L GAS
1973 V8 5.0L GAS
1973-1974 V8 5.7L GAS
1973 V8 5.7L LPG
1974 V8 7.4L GAS

For GMC:
Fits C15, C25, C35:
1973-1975 L6 4.1L GAS
1973-1974 L6 4.1L LPG
1973-1978 L6 4.8L GAS
1978 V8 5.0L GAS
1973 V8 5.0L GAS
1973-1978 V8 5.7L GAS
1973 V8 5.7L LPG
1976-1978 V8 6.6L GAS
1973-1978 V8 7.4L GAS
Fits C1500, C2500, C3500:
1979 L6-4.1L&L6-4.8L&V8-5.7L&V8-7.4L GAS
Fits K15, K25:
1973-1974 4.1L GAS
1973-1974 4.1L LPG
1974-1976 4.8L GAS
1977-1978 5.0L GAS
1973-1978 5.7L GAS
1973 5.7L LPG
1975-1978 6.6L GAS
Fits K1500:
1979 L6-4.1L&L6-4.8L&V8-5.0L&V8-5.7L&V8-7.4L GAS
Fits K2500:
1979 L6-4.8L&V8-5.7L&V8-6.6L GAS
Fits K3500:
1979 L6-4.8L&V8-5.7L&V8-6.6L&V8-7.4L GAS