What gorgeous Mustang Convertible! Like yourself, we happened to come across an unmolested, very low mile Mustang Convertible, also. In our case it had been barn stored for over 40 years when its 2nd owner become veery ill. By the time it was pulled out of storage it had about 13,000 original miles on it. The 3rd oner was (is) a Mustang Guy whose occupation involved buying and selling NOS and used parts for First Generation Mustangs, so he knew what he had acquired. He changed the original 14" dog dish wheels covers and steel wheels for a set of 14" Magnum 500 wheels, and replaced the age-cracked original GR78 x 14 tires with a set of FR70 x 14 WRL radials, which really look nice. He also replaced the original white top with a well made black top. Finally he added dual exhaust with some throaty, but nice sounding mufflers, and added an H-Pipe to help soften the otherwise harsher exhaust sound. There really was nothing else he felt it needed, and when we saw it for the first time in Summer, 2019, we agreed. And we agreed to purchase it for his asking price as it was fair. I did not even bother to take it out for a test drive! It started perfectly, idled smoothly, and revved (not to an excessive RPM) smartly. I figured if it had any engine or tranny issues it would be well worth repairing even at the asking price. Having made a living working on those vintage Mustangs "back in the day" I was not at all worried about any potential powertrain issues.
Other than being a Convertible with the Deluxe Interior and a 302 2v engine, C4 auto tranny, it was a fairly basic Mustang. The rear axle ratio was 2.79:1, for decent fuel economy, but it serves also to kill any prospect of being as nimble and quick off the line as out other pony cars. No matter, it was very well preserved. By the time we acquired it in July, 2019, it has just under 20,000 original miles on it. Currently it has just a little over 20,000 miles on it. We drive it locally, usually to a car show or just for fun on a nice day. We did add some upgrades to it, but nothing extreme.
The first things we did included adding Classic Air air conditioning as it worked out so nicely in our 1973 Mach 1. We also added an ACP full length center console, replaced the ***** light laden instrument panel with a Dakota VHX analog instrument equipped unit, replaced the rear taillights with a set of VintageLEDs.com taillight panels, installed a Garmin Drive 71 GPS with optional wireless backup camera display, and installed a DashCam. In the center console I removed the ash tray and fabricated a Power Panel with two 12 volt outlets, a dual USB outlet, and a digital voltmeter display. The front and side marker and turn signal bulbs have been replaced with LED lights, and of course the emergency and turn signal flasher units were replaced with electronic flashers. The sealed beam headlights were replaced by a set of Halogen lights, along with a headlight relay to keep the added current used by the Halogen bulbs from stressing the headlight switch internal circuit breaker device. For a final touch, because the cooling system upgrade I did on our 73 Mach 1 worked out so well, I replaced the stock cooling system with a dual electric fan based cooling system - despite the fact we hd no cooling system issues with the Convertible.
The paint on the rear of the trunk lid, just under the trunk lock assembly, was a little thin from the factory, and just beginning to show the tiniest bit of corrosion under the paint. Most folks would have missed it, but I noted it and had the lower part of the trunk lid's rear repaired. I did not want to repaint the entire trunk lid as the original finish (other than the one thin spot) was in really near-excellent condition. To help mask the possibility of the transition of the old and new paint on the trunk lid's rear surface I added a trunk stripe, which also gave it a much needed additional bit of edge to its look. To help give it a little more visual edge yet we added a front spoiler, knowing full well we would never be driving the vert anywhere fast enough to allow the front spoiler to do any kind of "good" in its handling.
We have several other pony cars, also. And any of them would absolutely smoke the 73 vert. But, the vert is our favorite pony car to go out in. Just because it is so much fun to have the top down on a nice day. Our 1969 Shelby GT500 remains my all time favorite car ever, but the vert is contending for #2 position along with the other two pony cars. Despite the 2.79:1 very steep rear axle gear set, the vert is plenty nimble around town, and is an excellent cruising machine at highway speeds. We are very pleased with how it looks, performs, and shows. There really is nothing more we plan to do with the vert, other than to thoroughly enjoy it for all our remaining years. As with our other pony/sorts/muscle cars, we plan to pass the vert down to some lucky heir...
In your one photo in this thread it looks like the LX is plated in TN. We reside in the western Upstate NY area (near Rochester), so it is not likely we will ever see both of our very original low mileage Mustangs together. But, I am betting yours is at least as nice as ours is. I do not mean to gush, but I really appreciate very low mileage First Generation Mustangs and Shelbys that have been kept in really good condition. I offer my personal congratulations on your good fortune in finding such a nice vehicle.
Following are some links to a few YouTube videos we posted. Some are "repair" or tinkering related, others are just to show some different aspects of the Mustang.
https://youtu.be/AACiuLR2YMk
https://www.youtube.com/watch?v=X2kgHn-XhVc