People who argue that it wasn’t GM – well, Pontiac – that created the first muscle car (the 1964 GTO) arguably have history on their side. Because there were muscular cars well before 1964 – including Rocket 88 Oldsmobiles and the letter series Chryslers of the mid-late 1950s. And one thing’s for sure: Chrysler more than any other manufacturer invented – and then perfected – the gentleman’s muscle car.
It began with the C, D and E series cars – which combined NASCAR worthy V-8s and an evr-increasing emphasis on style and luxury, as the letters and years rolled on. But the concept manifested in full flower in 1967, when Chrysler – through its Plymouth division – introduced the GTX.
Unlike the GTO – which was a bare-bones brawler (at least at first) with few amenities but plenty of horsepower – the GTX was both fast and fancy. Based on the Belvedere, the GTX was upgraded with its own unique (and flashier) front and rear panels, additional chrome, dual hood scoops and available racing stripes.
Under the hood lurked either the standard “super commando” 375 hp 440 big block or – for $546 added to the MSRP – the 425 hp 426 Hemi V-8. Either way, the GTX was fast. It was simply a question of whether to go faster.
440-powered cars were capable of getting to 60 in 6.6 seconds; the Hemi cut that down to 4.8 seconds. These cars were capable of outrageous – scary – top speeds, too. One-thirty-plus on 14-inch wheels and torsion bars. It took balls of steel to rotate the speedo’s needle all the way around the clock – but the engine was up to the job, if you were.
And if the Hemi wasn’t enough for you, Plymouth offered an R023 “super stock” option. It deleted much of what made a GTX a gentleman’s muscle car – including most of the insulation, the radio – even the hubcaps and heater core. But this elimination of surplusage cut down the car’s weight sufficiently to get it into the 12s – at which point, manners no longer mattered. According to Mopar historians, only about 55 of these “super stock” R023 GTXs were ever made – making them exceedingly rare (and expensive) cars today.
All GTXs received a performance-minded suspension consisting of six leaf rear springs, heavy-duty shocks and ball joints.
In ’68, Plymouth added a value-priced (and less well-equipped) version of the Belvedere coupe to the lineup. This was the famous Road Runner – and it was basically a de-contened GTX. The two cars shared the same body – but the RR came standard with the lower-prestige, lower-performance 383 V-8 while the GTX continued to come standard with the mighty 440. The GTX also came standard with a three-speed Torqueflite automatic transmission – unusual for a muscle car, but then, the GTX was a gentleman’s muscle car. The rougher RR came standard with a four-speed manual.
In the GTX, the manual four-speed was a no-cost option, while you had to pay an extra $206 to get the Torqueflite in the RR.
The GTX’s office was also appointed executive-style, with woodgrain appliques and more chrome accents. The differences in content were reflected in the two cars’ differing MSRPs. A new ’68 Road Runner listed for $3,034 – while the more genteel GTX carried a sticker price of $3,355.
In 1969, the under-hood ante was upped considerably with the arrival of the “440+6” option ($119 extra) which replaced the super commando 440’s single four barrel intake and carburetor with a wild-looking triple two-barrel set-up. The better-fed 440 now produced 390 hp – and could run with the more costly (and higher-strung) “street” Hemi – which in fact wasn’t very streetable. The Hemi was made for racing – and performed superlatively in the extreme conditions found on NASCAR’s high-speed ovals and could take the brutal life of quarter-mile bracket racer. But for street performance, the 440 was what you wanted.
Better still, a 440+6.
1969 was also the first year for the functional Air Grabber hood – controlled by an under-dash knob. Unfortunately, ’69 was also the last year for a convertible GTX. Henceforth it – and the RR with which it shared a body – would be sold as hardtop coupes only.
For 1970, Plymouth did something neat – something menacing – with the air grabber scoop. Instead of the previous fixed/hood-mounted deal that had an internal flapper mechanism for admitting cold air to the engine, now the entire scoop (with hungry shark decals on either side) rose up on command from the normally flat hood – giving clear notice of intent. Complementing this was a set of dummy rear brake scoops which the side racing stripes fed into like a high-speed airstream. And, for the first time, decent (from a performance point of view) 15×7 Rallye wheels with F60-15 Goodyear tires were available.
But there was a problem: The GTX was battling for customers with the increasingly similar RR – which was both lighter (due to fewer options/equipment) and thus, quicker – as well as less expensive. While GM (and Ford) also sold “twinned” (and even “tripled”) versions of one basic platform (for example, the Chevy Chevelle, Pontiac GTO and Buick GS all shared the same basic body by 1970) they didn’t compete within the same dealership. The Chevelle was sold at Chevy stores – the GTO at Pontiac stores. The Buick at Buick stores (and so on). But the GTX had to fight off the RR at the same Plymouth store. This hurt the car’s sales – badly. Only 7,748 1970 models were sold – and there was talk internally (within Chrysler) and without (in the automotive press) of the GTX’s imminent cancellation. It didn’t help that by this time – early 1970s – insuring any muscle car was becoming a Sisyphean undertaking. And insuring a big block muscle car? A 440+6 muscle car? A Hemi muscle car?
Forget about it!
But there would be a few more years of GTXs before the end finally came. And the end would not occur all at once.
The ’71 model featured the new “fuselage” look shared with the Dodge Charger and – again – the Road Runner. The smooth/rounded bodywork was a radical departure from the more baroque appearance of previous years. It had much in common, stylistically, with the very popular E bodies (Challenger and ‘Cuda) but was for whatever reason not as well-received. That’s putting it kindly. In fact, GTX sales wilted to just 2,942 for the entire model year – even though it had not been watered down underhood like many 1971 model year competitors. In fact, ’71 was arguably the high water mark for GTX muscularity. Both the 390 hp 440+6 and the 425 hp 426 Hemi were still available – with the 440+6 now putting out the same 490 lbs.-ft. of torque as the Hemi, but at considerably lower engine RPM (3,200 vs. 4,000 for the Hemi).
Still, a chill wind was blowing. ’71 would be the final year for the GTX as a separate model (the same thing would happen to the Pontiac GTO not long after). Now – for 1972 and thereafter until the end, in 1974 – the GTX became a mere options package you could order with the Road Runner. In other words, it had been subsumed by its budget-minded in-house rival.
The GTX package upgraded the Road Runner to 440 power under the hood – although by now the 440 was detuned and could no longer be ordered with the triple two-barrel induction system. Still, even “detuned,” the 440 delivered 280 SAE net hp – a very big number by 1974. And one easily increased, if one so desired, by retrofitting earlier year components, such as the triple carb intake and more aggressive camshafts of pre-1972. But even that door was closed next model year – 1975 – when catalytic converters were adopted industry-wide and with them, single exhaust and with that, smaller, less powerful engines. The 440 disappeared. 400s and 360s and 318s were as good as it got.
And it would get worse, soon.
Shadows and dust.
But, every once in awhile, you’ll hear the distinctive roar of a 440+6 coming on the cam, off in the distance. They may not be making them anymore, but at least they did make them – once upon a time.
Perhaps, one day, they will make them again… .
Throw it in the Woods?