1967 GMC C25/C2500 Pickup Engine: 4.6L V8; Position: Fan and Alternator;. 1967 GMC C25/C2500 Pickup Engine: 5.3L V8; Position: Fan and Alternator;. 1969 GMC C25/C2500 Pickup Engine: 5L V8; Standard Rad; without 62 Amp Alternator; Position: Fan and Alternator;.