A buddy in HS got a '77 2 door with the 460 (this was the mid 90's) and it had around 86k~ miles. Everything worked and ran fine. Great ride too. It had a hitch + air shocks, so it definitely saw some towing duty, but it never gave him any issues. Though nowadays the carb might need a rebuild, or better yet, an upgrade. If it still has a mechanical fuel pump, the diaphragm can let loose at any time if old. It's also easy to flood these if you pump it too much. Ignition control module on this era of Ford would quit for no reason, often, but was a cheap part. Car was the epitome of simple though.
I will say though, that stock, these things were horrid MPG abusers. I think 10 mpg is lucky. The 460 weighs a TON on these models as everything is cast iron (friend had it out on engine stand to bump power and the stand was actually sagging). If you are serious about an older 460 engine in a heavy Lincoln, I'd strongly suggest swapping in an aluminum dual plane intake manifold, tubular shorty headers, a modern 4 barrel, and possibly an aftermarket aluminum fuel pump. IF you have extra cash, upgrade the heads to something aluminum and consider changing the pistons to get something in the 10:1 range and a mild cam. Everything mentioned is mainly to drop SERIOUS weight (like a couple hundred off the nose) + bump power up to where it should be, which is the 400+ range with tons of torque.
Think they only offered open differentials back then with lazy highway gearing and a C6. If you'd be willing to upgrade to a modern 6 speed Tremec (could probably snag one from an older GM) and maybe run a 3:55 to 3:73, with a posi, along with all the weight reductions and power bump, it'd be a legit cruiser.
Other thing that might be a better deal, is swapping in a DOHC 4.6L from a Mark VIII. My '96 Mark VIII saw towing duty, and it wasn't until I had a 150 pound hitch assembly, 750 pound dolly, and 4k pounds of truck on the dolly, that it's MPG would drop to 10 on the highway. When it was just the car, it was 28 highway stock. 33 mpg after doing a bunch of tweaks, with 18-20 city.