The Plymouth Belvedere was produced between1951 through 1970, and at times it was Plymouth's top of the line model or mid level model. The Belvedere was introduced in 1951 to compete against the Chevrolet Bel Air, which had great success in it's first model year in 1950 as the first American two door pillarless hard top in the low price market. Through 1953 the Belvedere was actually the top of the line trim for the Cranbrook model line, before becoming it’s own model in 1954 when the Belvedere became the top of the model for Plymouth. Along with the new model, more options were available than just the standard 2 door hardtop.
Plymouth elevated the Belvedere line with the introduction of the GTX in1967. Being marketed as the “Gentleman’s Muscle Car”, the 1967 Belvedere GTX was a highly optioned version of the Belvedere with a unique grill, more trim, better engine choices, and more rigid parts found on racing cars. The “Super Commando 440” V8 engine was an option, or you could spend $550 more for the 426 Hemi. The Hemi was purchased more for drag racing as it had a higher top end than the 440, but only 720 Hemi powered 1967 Belvedere GTX models were sold. An extremely rare option that was not advertised on the 1967 GTX line is the “R023” option, which really wasn’t much of an “option” as it eliminated the hubcaps, heater, radio, carpet, and insulation making it a very capable racing car. The subtraction of these items dropped the weight down by a few hundred pounds, and the Hemi engine was tweaked to include multiple carburetors and turning the non functioning hood scoops into working scoops, giving the R023 GTX some serious horsepower. Both the standard 426 Hemi and the R026 versions claimed 425 bhp, but the standard Hemi was already thought to be above that number, meaning the R026 could well have over 500 bhp. Only 55 of these R023 models was produced, making them very rare today. Sales of the \full GTX line was respectable, with nearly 12,000 models sold.
Plymouth would sell nearly 19,000 GTX models in 1968, and the new Road Runner would be based off the same platform as the GTX. The Road Runner was marketed as a stripped down muscle car, and the GTX the higher end muscle car as it was $300 more. Styling showed in the price, as the GTX had more trim and options. Both models had nonworking hood scoops, and the standard engine on the GTX was the 440. The Hemi was expensive, and the 440 actually produced more torque making it better for street racing. Hemi’s dominated on the race track where they could reach their high revving maximum speed, but the Hemi’s did not sell well as only 450 were built. There was no racing option as there was in 1967 with the R023.
Sales for the GTX in 1969 fell due in large part to the Road Runner, as it now had a convertible and a 2 door hardtop version. Essentially the same vehicle other than mostly cosmetic trim and options, the Road Runner was a lot cheaper and you could get the same performance without the bells and whistles at a lower price tag. Performance options increased on the GTX as you could now get a Hurst shifter and an assortment of rear axles. The “Air Grabber” option turned the decorative hood scoops into fully working scoops with a shot off controller on the dash. Only 209 Hemi’s were sold, and mid model year the 440+6 engine option was available, which removed the single for barrel carburetor and replaced it with 3 two barrel carburetors for only $119 more. Sales fell to 15,602 for the model year.
The 1970 GTX model line was completely restyled for the 1970 model year, adding more curves and scoops as there were now non working rear air brake scoops. The convertible GTX was discontinued, but the same engine options were available including the 440+6 and Hemi. The Air Grabber scoop was available again, with a single opening once again controlled by an in dash switch. Only 72 Hemi powered 1970 GTX models were built. Sales dipped severely as less than 8000 were sold. 1971 was the last year of the GTX as less than 3,000 GTX models were produced, and the GTX would become an option package on the 1972 Road Runner.