I had the same idea about 6 years ago after finding one of those adapters in a C-body. I tried to retro-fit it into my '76 Duster and it was a no-go. Just not enough room, so I sold it.
FYI - The antenna hole on the passenger side fender is unique to '76 cars.
Too bad you're not in the San Diego area. I've got three clean fenders I need to get outta my life.
The rust is not bad at all. A light blasting (or wire wheel) and you're good to go. Lug holes are solid. Typical SoCal parts.
Not sure on fit of your Sport Fury.
I'm sure I probably have two buried somewhere in the garage. I remember pulling a couple 15x7's off a Cordoba a couple years back.
I can post pics shortly.
$75 and they're yours. I'm in Vista 92081 (at the Carlsbad northern border).
Here's a bunch of '76 stuff I have for sale.
I also have an NOS right side tail light bezel (no ad yet).
http://www.forabodiesonly.com/mopar/showthread.php?t=207029
http://www.forabodiesonly.com/mopar/showthread.php?t=207510
http://www.forabodiesonly.com/mopar/showthread.php?t=207629...
I'm unable to find a listing for the part#, perhaps someone else can help.
The part# stamped on the part is "3671 424". Handwritting on the box says "73 74 B.C. 360 440"