Interesting response. It sure seems the Chrysler models especially from 1969 to 1970 look a lot longer in the rear with the loop bumpers - so you are saying this is an optical illusion? And the Plymouth models especially look longer in going from 1969 to 1970 in the rear, also with adoption of the loop rear bumper. Where are you getting your dimensions?
Just curious, what is your background relative to Chrysler - i.e. source of information any link to Chrysler in the past?
Just a collector of information. Have specifications from Automotive Industries in the 1960's as well as Canadian Service Data Book, an annual publication of car specifications regarding brakes, ignition, suspension, exterior dimensions, engines, etc. CSDB started including external specifications in 1954 and I have issues dating back to 1936. CSDB gets their information from the manufacturers, as did AI. Each manufacturer filed a report with Automobile Manufacturers Association in Detroit with a complete set of specifications for all parts of the cars. Even the Canadian manufacturers filed the information with the AMA. And this information was used by CSDB, AI, Automotive News, Wards, and other publications.
For one, do not use photographs to compare lengths. What turns out depends on the angle of the shot and the lens being used. Photographers of cars for advertising purposes are notorious for making cars look longer and wider than they really are.
In the case of the 1969 and 1970 Dodges, my father owned a 1970 Dodge Polara sedan. I took his car in for some warranty work and parked it next to a 1969 Polara sedan. No question. The tail end of the 1969 was longer than the 1970.
For Plymouth, the difference is not that great. The Plymouth rear overhang was reduced 1.1" while the front was increased 1". Dodge, on the other hand, had 4.5" removed from the rear end and 3.1" added to the front. I think the big thing about the Dodge styling is the squareness of the front and rear ends from the sides on the 1970 models as compared to the 1969.
Also, when comparing lengths of cars, keep the comparison to the same body style - sedan vs sedan / 4dr hardtop vs 4dr hardtop / 2dr hardtop vs 2 dr hardtop, etc.