Discussion Forum - Northstar Chevelle Club

From

http://www.angelfire.com/tx/lonestarclassics/chassis.html

Since the A-car line of General Motors was to be aimed at a different audience for car buyers not desiring a full size car or a compact, this is where the senior compact (a Buick term) or midsize came into play.

*1964-67 A-bodies used the same frame design, but different models and bodystyles utilized various body mounting, while all frames had a 115 inch wheelbase, which is similar to the 1955-57 Chevrolet.

*1968-72 frames had two different wheelbases, a 116 and 112 inch wheelbase. Sedans , station wagons, and utilities like the El Camino used a 116 inch frame, and the frame is interchangeable, except that the sedan had non-boxed rails.

In addition to the length difference, the widths and features are different also. Pulled these images off a goggle image search