Looking at my first classic truck, what should I know?!
 

check ALL wiring, rubber hoses/ belts for dry rot or wear (they are commonly overlooked), floor boards, rad support, for rust. Make sure it drives straight as well as stop straight. The C6 was a damn good trans, not much went bad with them

also if he is claiming that much work i would want to see reciepts for work performed, if he can't produce then assume he is just blowing smoke...you don't want to buy someone elses problem

I would want to see before body work pics of the truck.

That it's NOT going to be a turnkey experience, no matter how much work was actually done by any P.O. It WILL need constant maintenance, and frequent repairs, and (increasingly-)hard-to-find parts, and (increasingly-)hard-to-find mechanics who know how it's supposed to work and how to figure out why it's not working that way, and... If you're not prepared to maintain & repair it yourself, you'd better have a LOT of disposable income to pour onto this truck. It will NOT be comfortable, convenient, reliable, durable, powerful, functional, or economical by modern standards. You might not even be able to register it for use on public roads in some places, so do a LOT of research before making a decision.

This is not a popular antique vehicle, so if you get bored with it or tired of it soon, it won't be as easy to sell as a '77 Corvette or Bronco.

My 1977 is unrestored. It is comfortable, reliable, and powerful enough to do what I want it to do. We have had it since new. It has never been behind a tow truck nor required a repair that couldn't be done at home.

Do you think that means the one he's looking at buying will be exactly as reliable? Do you consider your '77 to be as comfortable & powerful as a '17 F150?

I'm NOT suggesting that no one should own or buy old vehicles. But the OP asked what he should expect. And since this will be his first antique, his expectations are very different from yours & mine.

If the one he is looking at were truly restored, yes, it should be reliable.....The problem is many people consider a paint job and a few new parts a restoration, which of course it isn't

I consider my 1977 to be very comfortable. It rides smooth, drives straight and has good AC and heat. It is powerful enough to pull my 6k TT at interstate speeds with no problems.

The running gear in the truck he is looking at was and still is good stuff. A 460, C6, and 9 inch rear is a durable combo.

When that truck was new, it was very reliable. About the only weak link I can find fault in is the ignition control module. Sometimes they are problematic. Sometimes not,.though. My 1977 still has its original...They are cheap and simple to change,.though.

https://cimg1.ibsrv.net/gimg/www.f15...5c0bff970e.jpg
Jan. 2017,Beginning full cab off resto. Bought used 1984.
Bought mine in 1984 and have never driven it in winter months but did have small cab rust spots (2), plus the biggest issue for you to check are the frame cab mounts (look for new bushings but not 100% proof) and radiator core support/mounts both are very difficult to detect rust but can be repaired, look at the character lines noting that they are in alignment.
As for parts in general are not that difficult to find or fab if necessary, for not being popular there seems to be alot of people wanting them. No they are not Corvettes but by the ride one might wonder.
If done correctly, 10k for a like new daily driver is by far less $$ than a 2018 or 2019 making its poorer mpg look not as expensive plus a standout from the crowd of pick ups..
My point of view only with no offence to others.
Good Luck in your quest

https://cimg2.ibsrv.net/gimg/www.f15...8a907df920.jpg
351M stroked to 400 freshened up a little.
https://cimg2.ibsrv.net/gimg/www.f15...5144ade50e.jpg
Rusted out perch not visable... havent dug deep enough yet!

The only reliability issue i ever had and only once was the distributor control module (By the way its the only electronic control module) when it goes... you do not, bought a new one, two actually, replaced it (1/4" nut driver) and 10 minutes time i was going again. That was 1986, the other one i bought as back up is still in the small tool bag with nut driver waiting just in case.
These trucks are so easy to work on that its a sin how complicated the new ones are plus the outragious expense which makes up for the mpg. Just some effort and they can become quite comfortable ( seats from a 96' bolt right in ) and quiet with some sound deadner added.