The 1966 Chevrolet El Camino kept the same bed design as the 1964 El Camino and the 1965 El Camino, but the end sheet metal received numerous updates. The fenders of this El Camino featured a wrap-around design, and the new grille design was more extended and lower than previous years.

The 1966 El Camino was available in two levels of trim, including the base model El Camino and the El Camino Custom. These were equivalent to the Chevelle 300 Deluxe and the Chevelle Malibu trim levels.

The base El Camino featured more exterior trim than the previous year, including a bright tailgate latch, bright windshield molding, and chrome hood molding. The base El Camino chassis model identification number is 133- 13380 & 13480, depending on six or eight-cylinder engine choice.

The El Camino Custom featured the same trim pieces as the base model but also included bright body sill moldings, wheel opening moldings, roof drip moldings, windshield pillar moldings, and door frame moldings. Each configuration could be ordered with an inline six-cylinder or V8 engine. The El Camino Custom chassis model identification number is 135- 13580 & 13680, depending on six or eight-cylinder engine choice.

Buyers could have ordered several different El Camino exterior colors including Tuxedo Black, Ermine White, Mist Blue Metallic, Danube Blue Metallic, Marina Blue Metallic, Willow Green Metallic, Artesian Turquoise Metallic, Tropic Turquoise Metallic, Aztec Bronze Metallic, Madeira Maroon Metallic, Cameo Beige, Chateau Slate Metallic, and Lemonwood Metallic.

On the interior, bucket seats could only be optioned on the 13680 “Malibu” series pickup. The interior vinyl on the Custom was also of a slightly more luxurious design than that of the standard model.

Special gauge instrumentation could be optioned on any El Camino, just as with the Chevelle. A tachometer would be included in this package for any V8 equipped El Camino regardless of trim level, but the RPM range varied depending on engine choice. These tachometers could also be ordered separately from the gauge package on any of the V8 El Caminos. Base model El Camino interior colors were available in Fawn, Blue, or Red. El Camino Custom interiors could be had in Black, Fawn, or Red.

To complement the wide variety of available interior and exterior colors, were the available drive train combinations that could be optioned on the 1966 El Camino.

Base power was had by one of two six-cylinder engines: the Hi-Thrift 194 cid /120 hp or the Turbo-Thrift 230 cid / 140 hp.
Buyers who wanted more power could opt for one of the five available V8s: two versions of the Turbo-Fire 283 cid model were available with either 195 hp or 220 hp, followed by the Turbo-Fire 327 cid, making 275 hp. Finally, the two main Turbo-Jet 396 cid options were available in 325 or 360 hp versions respectively.

Although the 396 engine was available, there was no official 1966 El Camino Super Sport option. If an El Camino were optioned with the 396, it would receive the Turbo-Jet 396 flag emblems on the fenders as the only visible callout to the engine displacement. None of the SS396 Super Sport identifiers that were present on the Chevelle were available on the El Camino for 1966.

In early official literature, the 325 hp variant of the 396, the L35, was available along with the 360 hp L34. There were 1,865 known examples of the El Camino being sold with the L35 engine, yet only the total number of L34 and L78 engines sold among all body styles and service engines are known. The 375hp L78 was introduced midway into 1966, with only 3,099 units produced in total and an unknown amount in the El Camino.

There were also five different transmissions readily available in the El Camino for 1966. Manual transmissions were either a 3 speed, 3 speed with overdrive, or 4 speeds in either close or wide-ratio, and the only available automatic transmission was the 2 speed Powerglide.

Rear-axle ratios varied depending on a given engine and transmission combination. Standard equipment was the 3.36:1 axle for the base and 3.08:1 for Custom El Caminos. Some ratios were available on the Chevelle body styles that are not available here, such as the 3.73:1 ratio found on the L34 and L78 SS396 models. The 283 and 327 V8s could be optioned with either a 3.36:1 or 3.70:1 special purpose/mountain rear axle ratio.

All El Caminos and station wagons would receive vented gas caps, while all other Chevelles and Malibus would receive non-vented caps. All El Caminos came equipped with air-booster rear shocks, which could be inflated for extra load-carrying capability. Perhaps one aspect that differentiated an El Camino from a traditional pickup truck was the rear suspension, as El Caminos were equipped with four-wheel coil springs rather than rear leaf springs.

El Caminos were not built at all of the GM plants. Three plants built all of the available body styles, which were Baltimore, Fremont, and Kansas City.

Plants that did not build the El Camino were Atlanta, Flint, and Framingham. Additionally, all El Caminos sold in Canada during 1966 were produced in the U.S., so there are no Oshawa, Ontario built El Caminos in existence. In total, 458 El Caminos were exported from the U.S. in 1966.

About 35,000 1966 Chevrolet El Caminos were produced for 1966. The base El Camino total production was 9,321 units, meanwhile the El Camino Custom production totaled 25,798 units. These figures account for both domestic and exported units produced for the model year.