Well, I'm glad now that I made this post. It has brought up important questions I didn't ask.
Alan,
I went outside and took a look at the 73 26" rad support from the same angle as your photograph. They look the same from as close as my eye can determine.
In the 70-71 parts book, the 70 and 71 E Bodies have different part numbers for the side panels. However, that would be expected due to different hole patterns from year to year.
I just went and looked in the 74 book and it has the same part number as the 71 E Body.
Another 70 only part!!!
Well, that explains why mine looks like your 71 picture. Let's call them identical.
So now, is the 1970 different in form fit and function?
I just checked the K member numbers. Same part number for E Body V8 for 70 and 71, 3583074, so engine is in same location relative to frame.
(Also noticed that although E and B bodies had different part numbers in 70, they used the same 70 E Body K for both in 71, unless you got a skid)
As far as I know (but this IS Chrysler) radiator flanges didn't change widths between 70 and 71, so, at this point, I feel safe putting the 26" pieces I have on. I will go on the assumption that the different part numbers was due to hole layout changes.
Anyone have any more radiator information to add to this?
Robert