The 1967-1971 Plymouth GTX is the focus of this edition of Muscle Car Milestones. The GTX was Plymouth’s new “supercar” for 1967. Based on the Belvedere, the GTX came standard with big V8 power and a host of other performance features. This intermediate was marketed as a gentleman’s muscle car -- no greasy kid stuff here. Plymouth touted the GTX was the most exciting supercar to come out of Detroit in years. Let’s see if this declaration is true.

The 1967 Plymouth GTX was available as a hardtop and convertible. A walk around reveals dual hood scoops, dual chrome exhaust, and a pit-stop gas cap. Standard performance equipment includes a TorqueFlite 3-speed automatic, heavy-duty brakes, and heavy-duty front torsion bars, springs, shocks, and anti-sway bar. Inside, drivers are treated to front bucket seats, padded instrument panel, and seat belts. Serious buyers could check off the sports console, tachometer, and wood-grain steering wheel on the options list.

The standard engine was the 440 Super Commando pumping out 375 horsepower and 480 foot-pounds of torque. The performance enthusiast could opt for the 426 Street Hemi with 426 horsepower and 490 foot-pounds of torque. Both engines had a choice between a TorqueFlite 3-speed automatic or a 4-speed manual transmission.

Car and Driver said the 1967 GTX “is without a doubt the best-handling big Plymouth yet”. And who could argue? With a 0 to 60 time of 6.0 seconds and a quarter mile run time of 14.4 seconds, the 440 Super Commando GTX had what it took to take on the Pontiac GTO and Ford Fairlane. Car and Driver also marveled at the GTX’s handling abilities on winding roads claiming the car “sticks and sticks well, under practically all road conditions”. The hood scoops might have been fake but the GTX’s performance was as real as it got!

The GTX received a makeover for the 1968 model year. Last year’s boxy styling was replaced with smoother edges and a rounder body. A new feature that grabs your attention is the new side-facing hood scoops. And you could still get it as a hardtop or convertible.

The standard engine was the 440 Super Commando complete with a Carter 4-barrel carburetor, 2.08-inch intake valves, and 3.2 square-inch ports. With a compression ratio of 10.1:1, the 440 was good for 375 horsepower and 480 foot-pounds of torque. The 426 Street Hemi was still an option available to those who wanted more power and performance. With a 0 to 60 time of 6.3 seconds and quarter mile times of 14 seconds, the Hemi was a formidable competitor on the street and strip.

The automotive press raved about the Hemi’s performance. Car Life stated “Car Life has never tested a standard passenger car with the accelerative performance of the Hemi Plymouth GTX”. Car Life also ranked it in their 10 Best Test Cars of 1968 stating it is “the fastest quarter-mile full-size Supercar you can buy off a showroom floor”. The Hemi’s performance didn’t come cheap though. The Hemi tacked on a whopping $604.75 to the price of the GTX. That’s just the price you pay for being king of the road.

Not much changed for the GTX in 1969. There were a few styling tweaks here and there. Black lower body side paint replaced last year’s side stripes. The rear got recessed square taillamps. Also, the hood scoops could be made functional. A new Air Grabber was available for the 440 and standard on the Hemi. This feature was manually operated by the driver using a flapper valve that opened up allowing fresh air in through the hood scoops. Other goodies for 1969 included a Hurst shifter, heavy-duty radiator, and Sure-Grip differential.

The GTX was at the top of its game in 1969. Motor Trend pitted the GTX against several of its Detroit adversaries in a clash of the titans battle royale. The GTX faced off against other supercars such as the Chevrolet Chevelle, Dodge Charger, Ford Cobra 428 CJ, and Pontiac GTO. The GTX with the 440 V8 and automatic transmission was the fastest of the bunch from 0 to 60 and also quickest in the quarter mile. Motor Trend stated “Obviously, we were impressed by the performance capabilities of the GTX. It turned the best performance times in every category: acceleration, passing and quarter mile acceleration”.

1970 saw the GTX get a slight makeover with a new grille, a redesigned hood, and restyled back panel. Fake rear quarter scoops with GTX badging looked good but provided no fresh air to the rear brakes. The Air Grabber was brought back, but this time around, it featured a single scoop located on the hood’s power bulge. Just flip a switch to open the trap door and the engine gets to breathe fresh, cold air. The convertible was dropped from the lineup leaving buyers with only a coupe.

The big news for 1970 was the addition of the 440 Six Pack to the engine lineup. This leviathan pumped out 390 horsepower and a jaw-dropping 490 foot-pounds of torque. The Six Pack had Hemi-like performance at a fraction of the Hemi’s lofty price tag. Only 678 Six Pack-equipped GTXs left the factory in 1970.

1971 saw radical changes for the GTX. For starters, it was no longer based on the Belvedere. This year, the GTX’s styling revolved around the Satellite nameplate. The fenders and quarter panels were noticeably rounder and the front of the car featured a chrome loop bumper and round fog lamps. The GTX also featured a performance hood with side-facing scoops with stamped engine displacement.

Engine choices were the same as last year. The 440s each lost five horsepower but the Hemi’s rating stood pat at 425 horsepower. That’s pretty significant for 1971 considering most muscle cars were drastically losing horsepower due to lower compression ratios and stricter emission requirements mandated by Uncle Sam.

The 440 4-barrel was still an intimidating performer in 1971 on the street and strip. With a 0 to 60 time of 6.5 seconds and quarter mile finishes of 14.9 seconds, the GTX could still hold its own and then some.

This 1971 Plymouth Hemi GTX at the Wellborn Musclecar Museum in Alexander City, Alabama has the dubious distinction of having the highest-ever sticker price of a classic Hemi musclecar. This car’s sticker price topped out at an astonishing $6,593. That’s equivalent to $40,179 in today’s dollars. Since the car was a sales bank car, it was ordered with a ton of options including power windows, power sunroof, and vinyl roof. It’s quite a rare piece of musclecar history that is worth checking out if you’re ever in the area.

The GTX ceased to exist as a separate model after 1971. Sales had dipped to dismal levels and with rising insurance rates, the GTX was dropped. However, in 1972 through 1974, any Road Runner with the optional 440 engine was designated the Road Runner GTX. After that, the GTX name disappeared for good. Long live the GTX!