The 26" wide V-8 M-body radiators all look the same and will interchange. The police/taxi versions have a different part number. Over the years, I have man-handled maybe a thousand Chrysler radiators but never did a side-by-side comparison between the two M-body versions to determine the exact differences. I suspect either the fin density and/or the width of the tubes are where the difference is at.
Most of the early M-body radiators were either 1 or 2 cores deep (same tanks). The later ones are single core radiator but the core tube width is longer.
This picture was swiped from the internet to give a better explanation of the core type:
Note: these are for plastic/aluminum radiators - but core type is mostly the same.
The fin density is a bit more complex but more fins do allow more heat transfer. They are also more expensive to make and restrict air flow more.
For a mostly city driven car, a higher density fin count would be good. A mostly highway driven car, a lower fin count "might" be better (more air flow through the radiator to begin with).
BudW