Here's my valuation and rationale:
I'm starting this value out as a solid #3 car, and working backwards - $25,000. Now for the demerits:
1) Floors, as you show, need work and they are in a state that will almost certainly suggest the car was rusty elsewhere, and was fixed - maybe fixed properly, maybe not. Unless you have receipts for body work, as a buyer I'd suspect the body has been repaired and the car probably had the usual rust issues at some point. The concerning part is that the floors were allowed to get so bad, meanwhile the body shell looks pretty good - that suggests a previous owner that may have cut corners for the sake of "the image" while not really paying attention to the needs of the car. -$4000. It may seem like a large discount, but:
A) Body work scares people, especially when you have parts that ought to be rusty, but look perfect, right alongside other parts that are in dire need of rust repair -its a weird dichotomy that's going to drive the price down, even if the body work was done 100% correct. You can add about $2,000 back if you have full receipts for the body work AND it was done by a shop....I don't mean receipts for filler, sheet metal and a DA sander.
B) Body work, welding / structural replacement is not in every buyer's wheelhouse, if fact I'd say most buyers wont have the skills or experience to weld up a floor, assuming they even have a welder and know which end gets hot. Its one of those things where there are fewer buyers able to do the work themselves, which means its also one of those things that buyers will outsource, and will factor those costs into their offer. Even if your buyer does have the skills (like someone on this board perhaps) they also know that is a scary floor to a lot of people, and so again, it gives them bargaining leverage.
2) Non-original parts. Its a weird thing, most of us will put aftermarket parts on a car - electronic ignition here, headers there, etc, but its another story when a nameless previous owner has done the work and made the decisions. I note older headers, some sort of electronic ignition, aftermarket valve covers, what looks to be an electric choke Edlebrock carburetor. Wiring and hose routing is a little chaotic - not the cleanest installation and again suggests non-standard components and perhaps not a lot of attention to detail upon installation. Collectively - this devalues the car on two fronts. First, the non-standard parts and typical replacements detract from the car's value in a general sense, you may find a buyer that wants a "hot rod" and originality will matter less, but even those buyers often prefer to do the hot-rodding themselves, as opposed to inheriting another owner's decisions. Second, the installation and wiring / line / hose clutter in the engine bay again suggests a previous owner that just wanted to add parts, and didn't really spend the time to do the work with care and attention to presentation. This would reinforce the idea that the previous owner was more interested in the image and cut corners for the sake of expediency. -$2000
3 - Brakes - You mention disk brakes, but that master cylinder does not look like a disk / drum master. It looks like the stock single reservoir drum/drum unit with a single line out. This is where my lack of mustang knowledge will be an issue, because for all I know, Mustangs with disks in '65 used the same master as the Drum/Drum system, but I've never seen that on any car, ever. If its supposed to be that way, ok. BUT, if its not, and indeed that is the stock single reservoir unit for drum / drum brakes, then 2 things are a problem 1) The disks are not stock, they are aftermarket, so the question becomes - which kit, who did the work, do you have receipts...and 2) They are not installed correctly - might even be dangerous, frankly. If I were the buyer, and if that master truly is the drum/drum version, that would be an issue....- $1000
4) Looks like the car lacks power steering and no power brakes. Not the end of the world, but buyers have gotten awfully used to their power everything, cup holders, voice command, nav systems, etc. Lacking these power assists may limit your market a bit - some people wont buy a car that doesn't have those things. Others will, knowing they can add them, but then factor that into their offer. Obviously a third set will be just fine with manual brakes and steering, so it wont matter. Still, 2/3rds of your buyers will either care and not be interested, or reduce their offer to compensate -$500
So, where do we end up: $17,500. Valuation assumes paint presents well from 20 feet, seals and weather stripping are present and in good order (not new, but good) tires are fair and the car and its systems are operational - all gauges, fuel sender operates, lights, heat, radio if equipped, no funky noises or weird "quirks" you need to explain....such as
- "yeah, it does that on left hand turns" or " The wipers work, but only when you keep the switched pushed in" or "Its always made that horrible noise, I just drive it".