Bryan I know they look pretty much the same but, as stated they're not. Not only is the size actually different, there's a bunch of the parts of the assembly that are different.
Back in July I met a fellow Mustanger that had several '65s. He had a '66 underdash unit for one of them. I had a '65 set up, wanting to put it in my '66. After talking I found out we had both planned on refinishing our units to look like the respective year we needed. We worked out a swap so we each got what we needed and I got to compare the units side by side. That's when I found out they are indeed different sizes (as stated by Carlite)! That's only the start of differences (besides the obvious face difference). Sorry, but you need to locate a '66 unit!
