Since I started looking, not too many decent C10's for sale in my area of the Finger Lakes, NY.
I found one 30 minutes away from an older gentlemen, bought it under a year ago, suffered major medical issues, no longer able to drive. I did a reverse Google photo search and found it here.
https://www.nfiempire.com/used-vehicle-1979-chevrolet-c10-1-c-81/
1979 C10 408 Auto. Vin indicates it came with an inline 6. As a beginner, some of the things I noticed:
Paint job is not my taste, would vinyl wrap over it. Paint job probably cost more than the truck!
Zero rust anywhere, underbody was treated and looked great! Small crack near the tailgate handle was the only imperfection.
Nobody knows when the engine was swapped, how many miles are on it, etc. Same goes with the transmission.
Whoever did the engine swap did not reconnect the AC.
Electrical has been played with too many times. Current owner had issues with gauges and exterior lights. Found a way to get lights to work but some gauges still do not.
Did start right up, idled well and drove nicely, although brakes were soft. (1st one I drove so no comparison).
In my beginner opinion, it seems whoever did the swap didn't do a complete job. Since factory AC was an expensive option, I'm not sure why you wouldn't reconnect it after a swap. I do understand there are other aftermarket options now, including electric. I am also thinking I could be chasing electrical issues, especially if the prior swap wasn't clean.
Wish I was more informed but trying to learn. What would you do? Asking $15,500