What to look for in a used 340?

I was originally thinking of building a 340 because I though they were the best smallblock, but then I started doing research, around here people want stupid money for 340s! and you don't even know if they run. I ended up finding a 360, came out of a truck, ran pretty good, was cheap, only had 70k miles on it. Mind you I still completely rebuilt it, but its good to know that you can get a good core to start with.

360s were used in so many cars and trucks its not even funny, and you get the benefit of 20 extra cubes right out of the box as already stated.