What is a Square Body?

[Enceladus]

The 73-87 GM pickups were officially called the "Rounded-Line" trucks by GM’s design engineers - the people who designed them starting in 1967. It took over four years (1967-1972) to complete them before they were finally released for the 1973 model year.

The Rounded-Line name referred to the new aerodynamic cab which had a steeply-slanted windshield with rounded corners and rounded door frames that cut high into the rounded cab roof, unlike the 67-72 GM pickups which had squared door frames and so on. The 73-87 cab is far more aerodynamic than the 67-72 cab it replaced.


Brownell, Tim "Rounded-Line Models, 1973-1987" Chevrolet Pickup History (Truck History) Chapter 9 Page 88-89


The body of the 73-87 pickups was also more sculpted with the "waterfall flare" which flares out and then rounds down and the rounded pickup box corners (Fleetside only, not Stepside).


Wind tunnel testing during development, circa 1968


The waterfall flare runs the length of the vehicle down both sides, and (if fitted with the Fleetside pickup box) ties both sides together by continuing the waterfall flare around back across the tailgate.

I myself own a 1987 Rounded-Line Chevrolet V-10 Fleetside (currently under restoration)


Other references to the Rounded-Line name:

Chevytrucks.org uses GM's name for the 73-87 generation: http://www.chevytrucks.org/general/links.htm

And the classic truck site Stovebolt also uses GM's name: http://www.stovebolt.com/techtips/series.htm