The 1978 Concord offered slightly revised styling, a higher level of appointments and features as well as a greater emphasis on workmanship and quality that was prompted by the growing success of cars imported from Japan.

[3] The transformation of the old Hornet into the new 1978 Concord included positioning the new model as an upscale luxury compact with a competitive starting price in the mid-US$4,000 range (adjusted only for inflation equivalent to US$18,686 in 2023 dollars[4]).

The U.S. automobile industry has had a place "for a small company deft enough to exploit special market segments left untended by the giants" and under the leadership of "Gerald C. Meyers, AMC transformed the austere old Hornet into the more handsome Concord.

Front-end styling changed appreciably with a "waterfall" grille with a delicate chrome vertical bar treatment, quad rectangular headlights atop slim, wide clear parking and signal lights, and lighter aluminum bumpers were new for 1979.

A Popular Science road test of three traditional compact cars (AMC Concord, Ford Fairmont, and Plymouth Volaré) facing the challenge of GM's new front-wheel drive "X cars" (Chevrolet Citation and Oldsmobile Omega) summarized that AMC was committed to serve market segments not served by the other domestic automakers, and concluded that "Concord is the best-looking inside, and offers the plush feel of a big, expensive sedan.

Changes included the use of aluminized trim screws, plastic inner fender liners, galvanized steel in every exterior body panel, and a deep-dip (up to the window line) bath in epoxy-based primer.

[28] Although it was the oldest design and equipped with the biggest engine in a group of station wagons that Popular Science magazine road tested, the Concord recorded the best acceleration and fuel economy figures (compared to Chevrolet Malibu, Chrysler LeBaron, and Ford Fairmont).

"[36] Fuel economy figures for the 49 state versions in 1981 were:[37] Popular Science magazine highly recommended AMC's I6 as a "well-proven power plant" compared to the newly standard four-cylinder engine.

[30] The Concord that was comparison road tested had the 258 cu in (4.2 L) engine, and the car achieved better acceleration compared to the considerably smaller-engined Dodge Aries, Chevrolet Citation, and Mercury Zephyr.

[41] All AMC cars were marketed as the "Tough Americans" in print and television advertisements, indicating the presence of fully galvanized steel bodies, aluminized exhausts, and the comprehensive Ziebart rust protection processes included from the factory.

A new five-speed manual transmission made the options list, allowing a 151 cu in (2.5 L) Concord to achieve up to 37 mpg‑US (6.4 L/100 km; 44 mpg‑imp) on the highway, according to United States Environmental Protection Agency (EPA) estimates.

Sales slowed in the wake of the introduction of the Renault Alliance, which were more modern, space-efficient, fuel-efficient four-cylinder, front-wheel-drive cars compared to the rear-drive Concord with its aging platform.

A three-speed automatic transmission was optional with a column-mounted shifter in all three body styles, and ordering it included power steering, bumper guards, and a heater at no extra cost in both the sedan versions.

All three featured automatic transmissions, power brakes, power steering, 282 cu in (4.6 L) I6 engines (the 258 was standard on ECD models) with new-for-the-year Motorcraft two-barrel carburetor and 8.0:1 compression ratio, 3.07:1 rear gear ratio, light group (ashtray, glove box, hood, under the dashboard, and trunk (except on wagons)), custom steering wheel, woodgrain trim on the dashboard, a parcel shelf, clock, retractable seat belts, luxury upholstery, tinted windshield, bright molding package, "4.6" emblems ("4.2" on ECD), full wheel covers, and bumper guards.

The 06/S model came standard with power brakes with front disks, power steering, front sway bar, heavy-duty suspension (stiffer springs and shocks), Tremec 170-F four-speed manual transmission with Hurst linkage, Spicer 44 rear differential with a 3.31:1 gear ratio, heavy-duty cooling (coolant recovery tank, fan shroud, and three-line radiator), leather-wrapped three-spoke sports steering wheel, reclining high-back bucket seats, dynamic three-point front seat belts, a center console with armrest and Rallye gauges (clock, vacuum meter, ammeter, and oil pressure) with an ashtray for the rear seat occupants, digital tachometer, woodgrain overlays on the dashboard, parcel shelf, full light group (except dome), an AM radio with a passenger-side rear quarter panel-mounted antenna, dual remote-controlled body-colored mirrors, tinted windshield, blacked-out bumpers, VAM-designed sports steel grille, eight-spoke 14×6 steel wheels with blacked-out volcano center caps, and D70×14 radial tires.

All body styles included as standard equipment a rear defroster, reading dome lights, intermittent wipers, dual remote-controlled mirrors (new-for-the-year AMC squared chromed design), and AM/FM stereo radio.

The previous year's side panels with texturized vinyl tops were replaced by new high-trim fabric units keeping the carpet inserts but no longer having the map pouches.

This was an adaptation combining the central and front portions of the VAM American sedan with the rear third of the smaller Rally coupe creating a line of three- and five-door hatchbacks in a European style.

[70] The dire situation, coupled with a government decree banning the importation of automotive accessories deemed "luxurious and non-vital to the vehicle" took its toll on standard and optional equipment for all cars sold in Mexico.

Early in the year, a new head design was introduced for the 282 cu in (4.6 L) I6 engine with smaller spark plug openings and improved intake ports while still retaining the metal valve cover.

Cars with manual transmissions had a parcel shelf with two courtesy lights and a set of eight-spoke sports steel wheels with blacked-out volcano center caps as standard.

Both versions shared the same rear louvers, fender extensions, front air dam, side stripe, body-colored bumpers with guards and nerfing strips, shell-type door mirrors, roof Targa band, and mesh-grating grille design with round parking lights and central AMX emblem.

Tom Reffner, who won sixty-seven features driving an AMC Javelin during the 1975 season, campaigned his 1978 Concord AMX in races that included winning the April 8 ARTGO opener in 1979 at Wisconsin's Madison Capital Raceway with temperatures just above freezing.

[78] On 9 March 1978, the Concord driven by Buzz Cason and Richard Valentine placed 27th (out of 70 entered) with 162 laps racing the Six-Hour Champion Spark Plug Challenge at Road Atlanta.

[85][86] On 24 June 1982, Buzz Dyer set a record 37-position improvement when he started in 48th place in his Concord and finished the Portland race in eleventh, a feat that stood in the SCCA NTB Trans-Am Series until the 1998 season.

[97] Romer's previous negotiations included a promised restart of heavy-duty diesel truck production in 1977, along with a line of Subaru-bodied electric cars, using the original Brockway Motor Company facilities in Cortland.

[101] The Solargen's short production run of converted Concord station wagons was halted in late December 1979 due to delays in receiving a "major component", according to company officials.

[101] Subsequently, Solargen launched a $2.2 billion lawsuit against AMC claiming that the automaker conspired and reneged on a binding agreement to supply 3,000 Concords without a powertrain at $3,000 each and then not only raised the price to $4,593 per glider, but also delayed their delivery.

[107][108] The lawsuit also alleged that price increase and the delays were the results of pressure from General Motors "for the purpose of sabotaging Solargen's prospects of commercial success" and that AMC was in a conspiracy with GM in violation of the Sherman Antitrust Act.

[118] For the 1993 model year, Chrysler introduced the LH platform series of full-size sedans that was based on and built in the same Brampton, Ontario factory as the AMC-developed and Renault-derived Eagle Premier.