In 1968, Plymouth introduced their new line of 116" wheelbase cars with an advertising blitz called "The Mid-Size Five". The Mid-Size Five included the Belvedere, Satellite, Sport Satellite, RoadRunner and GTX. All body styles of each model (no station wagons) were considered part of the group, including 2-door hardtops, 2-door coupes, 4-door sedans and convertibles.

All of the Mid-Size Five cars, regardless of body style, were 202.7" long with an overall width of 76.4". The coupes were so-called because there was not a sedan-type frame around the front window. Chrysler seemed to be proud of the fact that the hardly-usable coupe "pop-out" rear windows kept children and pets securely inside of the car while still providing (their claim) excellent ventilation. Anyone who's owned a coupe knows better!

The Mid-Size Five featured a new fully padded instrument panel with a quirky new safety feature: all of the instrument and control knobs on the dash were recessed into the padding. Standard equipment located on the instrument panel were a brake system/parking brake warning light, temperature gauge, alternator gauge, gas gauge, oil pressure warning light, speedometer, headlight switch, 4-way flasher switch, ignition switch, windshield wiper switch, windshield washer switch, glove box and ashtray. Optional equipment offered were a tachometer or clock, A/C controls, AM stereo tape player, map and courtesy light. If you ordered the optional light package, it came with the cool time-delay ignition switch light. Anytime the front doors were opened, the ignition switch was automatically turned on and after a short delay the light would automatically go off.

All of these models had a 19 gallon gas tank, a laminated safety glass windshield, solid tempered rear window (including convertibles) and side windows, aluminized, reverse-flow mufflers with aluminized tail pipes, and large 15.6 cubic foot capacity trunk area.

Each of the five models was hyped by Chrysler's advertising department to appeal to a wide variety of buyers. For the economy minded: "Belvedere is Plymouth's mid-size economy car. Its graceful new body is designed to provide generous space for passengers and luggage, making Belvedere a comfortable car for both family and business use." The Belvedere came standard with 225 ci 6-cylinder engine (145 hp) or the 273 2bbl V8 (190 hp) and a 3-speed manual transmission. Optional powerplants were the 318 V8 (230 hp), 383 2bbl (290 hp), and 383 4bbl (330 hp). Optional transmissions were the TorqueFlite automatic and the 4-speed manual (not available with 225, 273 or 318). The Belvedere was available as a 2-door coupe of 4-door Sedan.

For the luxury minded: "Plymouth's Satellite is a high-styled entry in the mid-size car class. Smartly trimmed and modestly priced, Satellite offers a full range of all-new models." The Satellite came standard with the 225 ci 6-cylinder (145 hp) or the 273 2bbl V8 (190 hp) and the 3-speed manual transmission. Optional engines were the 318 V8 (230 hp), 383 2bbl (290 hp) and the 383 4bbl (330 hp). Optional transmissions were the TorqueFlite automatic and the 4-speed manual (not available with 225, 273 or 318). Other standards on the Satellite were full-length body side mouldings, wheel well mouldings, drip rail mouldings and brushed aluminum tail light panel trim. The Satellite was available as a 2-door hardtop, convertible or 4-door sedan.

For the sportier crowd: "The Sport Satellite is a youthful car styled and trimmed with a sports-car flair inside and out. Wood grained trim on instrument panel and doors and all-vinyl bucket seats keynote Sport Satellite's interior." The Sport Satellite came standard with the 318 V8 (230 hp) and the 3-speed manual transmission. Optional engines were the 383 2bbl (290 hp) and 383 4bbl (330 hp). Optional transmissions were the TorqueFlite automatic and the 4-speed manual (not available with 318). Other standard features on the Sport Satellite include body side accent stripes, wide sill mouldings, wheel well mouldings and full-length applique between tail lights. Sport Satellite was available as a 2-door hardtop and convertible.

For those who wanted strictly performance: "Plymouth's new RoadRunner is a fast fun car. Quick on the go, it shows its competitive spirit as it stands poised for action! No frills, no tinsel. When equipped with the optional 426 Hemi V-8 engine, RoadRunner is a lean, hungry car packed with power for action, built tough for sanctioned road-and-track events and flashing an eager, searching look that says 'show me the competition!'."The RoadRunner's standard engine was a special 383 4bbl with 335 horsepower and the 4-speed manual transmission. Optional were the 426 2X4 Hemi and the TorqueFlite automatic transmission. For this year, RoadRunner was only available as a 2-door coupe. Other standard features on the RoadRunner were black crackle finish un-silenced air cleaner, chrome plated oil filler cap and special air cleaner emblem, heavy duty suspension/ ball joints/torsion bars/leaf springs, RoadRunner nameplates and decals, Beep Beep horn and side facing hood scoops.

And finally a Mid-Size Five entry that was marketed to the performance buyer who also wanted the fancy stuff: "GTX looks like a hot performance car, sounds like a hot performance car, handles like a hot performance car and goes like blazes! Big-engined, firm-suspensioned, wide-stanced and sport-trimmed, GTX has competition power and handling qualities." The GTX's standard engine was the 440 4bbl with 375 hp with the TorqueFlite automatic transmission. The options were the 426 2X4 Hemi and the 4-speed manual transmission. The Sure Grip differential was required with the TorqueFlite automatic. The H.D. Sure Grip performance axle was required with the 4-speed manual and the 426 Hemi. Both differentials were extra cost options. Standard features on the GTX were bucket seats, woodgrain trim on the instrument panel and doors, outward facing hood scoops, GTX emblems, lower side dual color stripes, wide sill mouldings, wheel well mouldings, chrome exhaust tips, heavy duty ball joints/torsion bars/springs and shock absorbers, and rear deck lid treatment with red Scotch-Lite inserts between the tail lights, exclusive to GTX. The GTX was available as a 2-door hardtop or convertible.