31: GMC Sprint SP
The GMC Sprint SP was actually a corporate cousin of the El Camino and one that was way overhyped at the time. There was nothing inherently wrong with the GMC Sprint, but the fact that GM did nothing to differentiate the car left buyers confused. The only differentiating things between this truck and an El Camino was the GMC badges that were plastered all over the vehicle.
GMC had many sales successes around this time period, but the Sprint wasn’t one of them. Perhaps if the car/truck had been more unique in the styling it might have garnered more sales success. Still, the GMC Sprint SP is a pretty unique vehicle that you don’t see very often. If you are lucky enough to find one of these they are identical to the El Camino in every way.