1973 - 1977

 The most extensive redesign in its 10-year history marked the 1973 Chevelle, and with it marked the end of hardtops as we knew them. The newly-named "Colonnade Hardtop" featured a semi-fastback roofline, frameless door glass and

 fixed, styled "B" pillars, structurally strong enough to contribute to occupant safety of a roll-over type accident. GM had anticipated Federal roll-over safety standards that ironically didn't materialize. Distinctive rear quarter glass on 2-door coupes and new side windows with styled center pillars were featured on 4-door models. Rear windows on coupes no longer opened. In addition to the new roofline, front and rear ends looked markedly different this year as 1973 was the year of the federally-mandated 5 mph (8.0 km/h) front bumper, adding to the car's length. Additional new body features were an acoustical double-panel roof, tighter-fitting glass and flush style outside door handles. Wheelbase dimensions were retained; a sporty 112 inches (2,800 mm) for coupes and 116 inches (2,900 mm) for sedans and station wagons, but bodies were five inches (127 mm) longer and an inch wider with a 1-inch (25 mm) wider wheel track. The station wagon, available in 6 or 9 passenger seating, featured a new counterbalanced liftgate which allowed for easier entry and loading up to 85 cubic feet.[11]

 

1973 models also introduced molded full foam front and rear seat construction, a flow-through power ventilation system, an inside hood release, refined Delcotron generator and sealed side-terminal battery, a larger 22 gallon fuel tank, and "flush and dry" rocker panels introduced first on the redesigned 1971 full-size Chevrolets. Another structural improvement was a stronger design for the side door guard beams.[11] New options included swivel bucket seats (with console) for coupes and Turbine I urethane (backed by steel) wheels, as was the instrument gauge cluster. A power moonroof was an option 1973-75.[12] Interior roominess of the '73 Chevelle was improved, particularly in the rear. Headroom was up slightly and shoulder room gains were by 1.6 inches (41 mm). Rear seat legroom was up 3.5 inches (89 mm) in sedans. Another was a 15.3-cubic-foot (430 L) luggage capacity, an increase of 2.5 cubic feet (71 L) over 1972 models. Still another benefit of the new body designs was greatly improved visibility, up 25% in coupes and wagons, and 35% in sedans. The unusually thin windshield pillars also contributed to much better visibility.