these were in my trunk...they appear to be radiator brackets......but I don't see how they would work with this car let alone the radiator, I think their either for another car or not what I think they are.

on a side note is there a website where all ford part numbers are listed?

 

They look like upper/lower radiator mounts but they didn't come from your car. D6 is Ford for '76. Close as i can find D6DE-AA would be from a '76-'79 6cyl. ford/merc. model.
I think teh 3rd space 'D' is for midsize car like Maverick, Granada, LTDII, etc.

Here's a handy decoder site:
http://mustangtek.com/FordDecode.html
Jon

 

They are not for your car but they can come in handy if you ever want to switch to a crossflow style rad..They may be off of a pickup truck..

 

As has been stated, these are Mid 70's FORD radiator mounting parts to fit the top of the crossflow Radiator.

70 Mustangs are different.

Dan @ Chockostang