In 1967, the mid-sized Plymouth Belvedere gained a new trim line: the GTX 440, the “gentleman’s muscle car” (along with the 300 letter cars).
The GTX was created in reply to questions used by people like Hot Rod’s Eric Dahlstrom: "How will you tell it's a hemi?" One possible problem with the Street Hemi, the most powerful engine to come out of Detroit in 1966, was that it was installed in cars that, except for discrete 'HEMI' badges, looked no different from those powered by 318s and slant sixes. "It pays to advertise," claimed Dahlstrom, and that's what Plymouth did for '67.
The two-door hardtop body was outfitted with fiberglass simulated hood scoops and optional racing stripes, a blacked out grille and on the rear fender a racing style pop open gas cap. Inside was a 150 mph speedometer and optional electric tachometer mounted out of the way on the optional center console.
Plymouth designer/stylist John Samsen wrote, "At the time we designed these cars [1964 to 1966 Fury and Belvedere], the guidance from Sales was to make the cars look as wide as possible, front and rear. Quad lamps were mandated on all but the A body cars at that time. Being smaller than standard lamps, they were easier to fit into the grilles.”
Standard features included the 440 Super Commando, TorqueFlite automatic, bucket seats, Charger-like “pit stop gas cap,” front and rear seat belts, and energy-absorbing steering column; options included front disc brakes, four-speed manual transmission, and (apparently hard to keep in original condition) wooden steering wheel. As with all Belvederes, the front suspension used torsion bars and an anti-sway bar, while the rear suspension relied on leaf springs; but the torsion bars were heavier duty than standard models, with oversized anti-sway bars, heavier duty leaf springs, and the beefed-up 727 TorqueFlite automatic transmission.
The GTX came with a standard 440, which had been brought out in 1966 for full-sized cars with 365 gross horsepower. Chrysler prepared the engine for its first appearance in a mid-sized car by adding ten horsepower, via bigger valves in redesigned heads. It came with extra-large throttle bores, dual snorkel air cleaner, hot cam, oversized ports and valves, and cast headers.
The optional engine was 14 cubic inches smaller, but with its legendary Hemi heads, dual four-barrel carbs and slightly higher compression ratio, the 426 Hemi produced 50 more horsepower. It was also less "streetable," making the 440 a more practical choice. Hemis were installed in 125 GTXs, 14 in convertibles (10 with Torqueflite; 7 with four speed transmissions) and 108 in hardtops (48 Torqueflites; 60 four speeds).
On all Plymouths, the Hemi got a 3.23:1 axle ratio with the automatic; a manual transmission required the Sure-Grip differential (optional with automatic), and came with a 3.55:1 rear axle ratio. The 440 had the same ratios, except that a 2.94:1 ratio was available with the automatic unless Sure-Grip was ordered. The 2.94:1 was not recommended. (These ratios were similar to all the Plymouth engines, including the slant six, except for the 3.55:1, which was only standard with four-speed manuals on the 440 and Hemi, and optional with the slant six.)
1967 Belvederes, including the GTX, had standard dual hydraulic braking, with one system for the front and another for the rear; front disc brakes were optional. Standard brakes for the Belvedere V8 were 10-inch self-adjusting drums, 2.5 inches wide, with bonded linings; a separate mechanical foot operated parking brake acted on each wheel. For GTX, drums were bigger: 11 by 3 inches, with 11 x 2.5 in the back. GTX got wider wheels — 14 inches, along with every other Plymouth, but 5.5 inches wide. (5.5 inch widths were also used on wagons, trailer towing packages, and any car with a Hemi.) Tires were 7.75 x 14 Red Streaks.
The GTX shared most Belvedere dimensions: 116 inch wheelbase.
The car magazines, on seeing the “small” Hemi and the bigger 440 in the engine bay, enjoyed themselves with research on whether the cubic inches or head design would carry the day; in general, the Hemi would win the quarter mile, but since the 440's torque peaked at 3200 rpm while the Hemi had to wait until it reached 4000, and was harder to tune, a race was often tight, and well-driven, well-tuned 440 cars could beat Hemi cars.
The Hemi was available only in the GTX in 1967; in 1966, it was, in theory, optional across the line, and many 1966 buyers went for the Hemi in stripped-down bodies. To get the same engine in 1967, the buyer had to pay for the fancy GTX trim, leaving many "little guys" out in the cold. The result of that was a decline in Hemi car sales, from 1,510 Hemi-powered Belvederes made in 1966, to 125 were produced in 1967. The easier-to-manage and far cheaper 440 took away some Hemi sales; Plymouth would address the “budget body” problem with a vengeance in 1968. ("Beep-Beep!")
In 1968, the line was restyled. The most noteworthy difference was the roofline, which was changed to follow the Charger. 1968 and 1969 models had standard flip out rear quarter windows. The new "Coke bottle styling" was attractive and eye-catching, and quite a departure from past models.
Despite these changes, U.S. GTX sales were a meager 18,940 units, mainly hardtops but with over 1,000 convertibles; yet, it was the best sales the GTX would ever achieve, partly because of the newly introduced 1968 Road Runner. The Road Runner had tremendous acceleration and strong cornering, but without the luxuries of the GTX — and without its high price (the GTX started at $3,329; the Road Runner started at $2,870 with its base four-barrel 383). The formula used by the 300 letter cars and Imperials had not been entirely sound — many buyers wanted the performance but not the other goodies. Road Runner outsold the GTX by more than two to one in 1968, and within the Road Runner line, the cheaper coupe outsold the hardtop two to one. Road Runners were also around a hundred pounds lighter than the GTX, helping their speed, and came with a more “fun” appearance package. Still, the GTX came with more creature comforts, including carpeting and sound insulation.
For 1969, Plymouth added a cold-air induction package using hood scoops as a GTX option; it had a new grille and rear styling. GTX took the Road Runner package and added a heavy duty battery, exhaust trumpets, stripes, hood scoops, bucket seats, vinyl trim, heavy duty automatic and suspension, deep-loop carpeting, numerous trim pieces, and the standard 440 with performance cam and bigger valves and ports. Still, just 15,602 would leave American dealerships in 1969, as muscle car enthusiasts chose less expensive vehicles, and the writing was on the wall. Road Runner was outselling GTX by a factor of five to one, with a base price advantage of $2,945 to $3,416 (the weight difference was now fairly minor).
1970 was the Plymouth GTX’s last year as a unique model; again, the grilles were changed, along with the hood and fenders, and rear panel. GTX went up to $3,535, and the slow-selling convertible (just 700 were made in 1969) was no longer available.
1971 was the last year for the GTX as a separate model; it had outlasted the Belvedere itself (at least, the Belvedere name, since the car was simply renamed to Satellite), due to slow sales. Plymouth moved over 66,000 Satellites and over 150,000 of the Fury III, more than all the big Plymouth muscle cars combined, compared with 24,000 Belvederes. The big hit, the new Plymouth Duster — a car management reportedly turned down — made all other cars look unpopular, with nearly 200,000 Dusters produced in 1970. The Duster probably clobbered the sales of the Road Runner, which had promised to be another GTO. Perhaps had Chrysler supported and kept the Duster, it would eventually have become another Mustang, but that’s a question for another article.
1971 was the big body style change (akin to Roadrunner and Charger), a continuation of the "fuselage" style; aircraft and space motivated, John E. Herlitz’s groundbreaking styling featured swoopy lines, and large, looping bumper/grill assemblies. One of the more functional changes was the extension of the rear track by nearly three inches, increasing stability and improving cornering. Other changes included new interiors, sunroofs, flush door handles, ventless side glass, functional air-grabber hoods, and the famous Tuff steering wheels.
Inside the GTX, contour bucket seats became standard (they were optional on the Road Runner). The Tuff steering wheel was a mere 14.5 inches in diameter but a full inch thick. Rear spoilers were optional along with rear window louvers. Brakes remained the same size, but wheels expanded to 14 x 6, with optional 15 x 7 rims. The wheelbase was a little shorter, at 115 inches; length was 203.2, height 53.0, width 79.1, and maximum track 62 inches. The front torsion bar had a .92 inch diameter; the front stabilizer bar had a .88 inch diamter. In back, the left side leaf springs had five leaves and two half-leaves; the right side had six leaves.
The 440 put out 370 gross horsepower, 305 net, at 4,600 rpm; torque was 480 lb-ft at 3,200 gross, 400 net. The standard rear axle had an 8 3/4 inch ring gear diameter and a 3.23:1 ratio.
The GTX, now in its fourth and last year as a “model” rather than a trim level or option package, hit just 2,942 sales in the United States — making the terrible 1970 GTX sales seem downright positive. In contrast, Duster continued to soar with over 185,000 sales, showing that price does matter, at least for value brands.
Patrick Drake wrote: I bought my 1971 GTX new from a dealer in La Puente, California. It was built at the L.A. assembly plant in September 1970. It was the last 440 vehicle sold in California (I had dealers check for any available). It competed at Lions drag strip and Orange County International for a couple of years before I moved back to Canada. In 1986 it came in second in bracket #2 at the U.S. Mopar Nationals. It now has 70,000 miles on it and the engine is original and as strong as ever.
1972 was the year Chrysler's famous Electronic Ignition System became standard across the board. Introduced on a limited basis in 1971, it was being installed on all engines late in the 1972 model year. The points and condenser-free system helped cold weather starting and reduced misfiring.
In 1972, the Plymouth GTX was dropped as a model line of its own, and made into a Road Runner option. Any Road Runner ordered with the 440-4 engine in 1972-1974 was, technically, a GTX option package. This didn't mean much more than having the larger 440 engine, heavier torsion bars to hold it up (0.92" diam. instead of the stock 0.88"), and three "GTX" emblems - one for each fender and one on the trunk next to the "bird-in-circle" decal. Engines were essentially the same as in 1971, except for electronic ignition; horsepower ratings fell as the switch from gross to net was made universal and gross figures were no longer reported. Sales fell for 1972, partly on misunderstanding of the rating system, but went back up (though not up to 1971 levels) for 1973 and 1974. (Thanks, Dave Wilson.)
1972 was the last year for the 440 Six Pack; John Shoe wrote that they were actually built late in calendar-year 1971.
Even with the GTX included, the Road Runner fell from its prior, strong-for-a-muscle-car sales to a meager 7,628 units produced — an astounding drop even if one accounts for the Duster, which had exceeded a whopping 212,000 units. GTX sales were not broken out separately, but could not have been good.
For 1973, Plymouth switched from loop bumpers to the usual grille-over-bumper arrangement due to energy absorbing bumper rules. Plymouth did a better job of integrating them into overall styling than some other manufacturers; but Dodge managed to keep the Charger’s loop bumper, even though it was backed up by a full-width reinforcement beam and heavy-gauge steel support structure. Obviously visible in this year (and remaining on many cars through 1976) were elastomeric guards designed to keep the bumper from slipping over or under another car's bumpers during a low-speed collision.
The Cleaner Air System routed a varied volume of exhaust gas to the incoming fuel/air mixture to lower peak burn temperatures; it also used an orifice spark advance (frequently disabled by owners after the orifice clogged) and an electric assist choke.
Disc brakes were made standard on all 1973 Plymouth cars except the six-cylinder Valiants, and even for these cars, they were optional. Power assist was standard on all Furys, Duster 340s, and all wagons.
In 1973, the Road Runner was similar to the Satellite, but with a “power bulge” and simulated vents on the forward corners. (1973 details) The GTX was still the 440 engine package for the Road Runner, whose engine selection ran from the 318 through the 340, 400, and 4 barrel 440s (but not treble two-barrel arrangement). The Road Runner made a bit of a comeback, reaching 19,056 units produced, but that simply was not enough.
The year 1974 was essentially a continuation of 1973 for the Satellite series. The Satellite was dropped, in its many incarnations; Road Runner, though, despite selling just 11,555 units in 1974, was kept on, but the slow-selling GTX trim line was cut. For 1975, Road Runner would move to the Fury body, and sell just over 7,000 units; that would be its own last year as a separate model, though it would be available, as GTX had been, as an option/trim package.
Though not many people bought a Plymouth GTX, it remains a staple of car shows, and was moderately popular in movies, featured in Brewster McCloud, Fifty-Two Pickup, Joe Dirt, and Tommy Boy; it was also the car driven by Angel in the 1999-2004 TV series Angel.