What I've learned is to start off with the best you can afford and build on it from that point. The two cars posted would need to be damn near free for me to want to move forward. Not that they're junk, it's just with the amount of work they need it wouldn't make sense for me. I don't like rust.
A quick search in the local classifieds shows a few 65-67's that are decent driver quality for $3500-7000....that's about what it'll cost to rebuild a motor/transmission.
The good thing about these cars are they are cheap with low resale value. If you can't find patch panels chances are you can find a complete car for next to nothing and cut it up.