Editing Station wagon (section)

====Clamshell====
{{Multiple image
| align = 
| direction = horizontal
| total_width = 300
| image1 = 1971 Buick Estate wagon rear.jpg
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| caption1 = Closed tailgate
| image2 = 1971 Buick Estate Wagon with clamshell-type tailgate system 3of7.jpg
| caption2 = Tailgate folded open
| footer = 1971 [[Buick Estate Wagon]] with a "clam shell" tailgate
}}

Full-size General Motors, from 1971 through 1976 station wagons ([[Chevrolet Kingswood Estate|Chevrolet Kingswood, Townsman, Brookwood, Bel Air, Impala, and Caprice Estates]]; [[Pontiac Grand Safari|Pontiac Safari and Grand Safari]]; [[Oldsmobile Custom Cruiser]], and the [[Buick Estate]] models) featured a 'clam shell' design marketed as the ''Glide-away'' tailgate, also called a "disappearing" tailgate because when open, the tailgate was entirely out of view.<ref>{{cite web |last1=O'Clair |first1=Jim |title=Collectible Clamshells |url= https://www.hemmings.com/stories/2008/05/15/collectible-clamshells |work=Hemmings |date=15 May 2008 |access-date=19 January 2023}}</ref> On the clamshell design, the rear power-operated glass slid up into the roof and the lower tailgate (with either manual or optional power operation), lowered below the load floor. Manually operated types included a lower tailgate counterbalanced by a torque rod similar to the torque rods used in holding a trunk lid open. It required a {{convert|35|lb|kg|adj=on}} push to lower the gate. Raising it required a {{convert|35|lb|kg|adj=on}} pull on a handhold integral to the top edge of the retractable gate.<ref name="popsci">{{cite magazine |title=The '71 Wagons, Big Changes Coming Up |magazine=Popular Science |date=October 1970 |pages=74–75 |first1=Jan P. |last1=Norbye |first2=Jim |last2=Dunne |url= https://books.google.com/books?id=QwEAAAAAMBAJ&q=%22glide+away%22+tailgate&pg=PA75 |via=Google Books |accessdate=31 March 2022}}</ref> Power-assisted operation of both the upper glass and lower tailgate became standard equipment in later model years. Station wagons with this design were available with an optional third row of forward-facing seats accessed by the rear side doors and a folding second-row seat. They could accommodate {{convert|4|x|8|ft|m|adj=on}} sheets of plywood or other panels with the rear seats folded. The clamshell design required no increased footprint or operational area to open the cargo area. This enabled access even if the station wagon's rear was parked against a wall. 

The GM design, as used in a Pontiac Grand Safari, with a forward-facing third-row seat and the clamshell tailgate, was less popular with consumers and was described as the "least convenient of all wagon arrangements" with difficult passenger egress and problematic tailgate operation in comparison to the 1974 [[AMC Ambassador#Seventh generation|AMC Ambassador]], [[Dodge_Monaco#Third_generation_(1974–1977)|Dodge Monaco]], and [[Mercury_Colony_Park#Fifth_generation_(1969–1978)|Mercury Colony Park]], full-size station wagons conducted by ''Popular Science'' magazine.<ref>{{cite magazine |last1=Norbye |first1=Jan P. |last2=Dunne |first2=Jim |title=The Big Wagons: They do a great job—at a high price |magazine=Popular Science |date=May 1974 |volume=204 |issue=5 |pages=12, 21, 24, 26, 28 |url= https://books.google.com/books?id=j989VTOlPwMC&pg=PA12 |via=Google Books |access-date=31 July 2022}}</ref>
Subsequent GM full-size wagons reverted to the door/gate system for its full-size wagons.