So after several years I'm finally getting around to putting a correct radio antenna on my 71 Barracuda. After snapping off the junkyard antenna mast while separating it from the base, I was frustrated. I had another base with same numbers, but the cable wouldn't fit, even after some dremeling with a carbide cone. I bended up disassembling both bases (yes it can be done), and assembling one that worked. After all this, I pull out the old incorrect antenna.
This is when I notice the proper antenna nut will not come close to fitting the hole in the fender. WTH? Could my fender have been replaced with a T/A front fender? so far I see no evidence the hole was welded up before.

There should be a chrome bezel, nut, and the base/mast....Here's a pic off ebay...Are you missing something ????

I'm missing two things. One is the gasket. And the other is a hole in the fender the bezel tab and the nut will fit into.

I thought the correct 71 antenna had a 90 degree bend at the base?

I have seen those but can't vouch for straight vs 90° as mine wasn't correct when I got it.

Wow! Happy happy joy joy! I knew I had one metal plug cutter in my toolbox. It was my dads. I just ran it thru a piece of cardboard. The antenna nut fits perfectly. So I'll punch it out. Couple of layers of masking tape inside and outside the fender to keep paint from chipping. I should get a nibbler and notch for the bezel.