The antenna on my 82 since I've owned it has been just the threaded stub. I have plans to replace it with a CB antenna and splitter to use it for both CB and AM/FM. Does anyone know the diameter of the hole in the fender? I'll probably do a fender/hood mount antenna and run the cable through the center of a antenna hole plug. Or use something like this: I saw photos of someone on ih8mud who did this on their 80 series Land Cruiser and it looked pretty clean. I'd like to order all the parts to have on hand before I start disassembling things, though in a pinch I'll just take the antenna off and measure it (and report back here for posterity).
I figured out that I could loosen up the antenna base enough to get some calipers in to measure the hole without dropping the antenna assembly into the fender (which is what I was worried about). The hole is slightly under 1 inch diameter. Batteries were out on the calipers and super precise wasn't necessary. I added that Garmin plug to an Amazon order--it may be slightly big, but its a soft rubber so I can likely stuff it in there with the coax running through.