The first generation of GMC C/K was introduced for the 1960 model year. The GMC C/K was an upmarket version of the Chevrolet C/K, and was the successor to the GMC Blue Chip Series. Four main variants were produced, 1/2 ton, 3/4 ton, 1 ton, and 1.5 ton, these variants were known as 1000, 1500, 2500, and 3000. Four wheel drive versions were designated with a 'K' (K1000, K1500), while rear wheel drive versions did not feature a letter designation, unlike its Chevrolet sibling. Over the course of the first generation's life, a selection of inline six and V6 engines were offered on the C/K, ranging from a 230ci I6 to a 305ci V6. These trucks have also gone on to be Custom builds from a variety of builders. Production of the first generation C/K ended in 1966, when it was replaced by the Second Generation GMC C/K.