340 Block Bored to 4.160????? Help

Hi guys, been on the site for a while now but this is my first post.
I picked up a 73 Dart Sport last year with a 340 in it. I opened it up and just did a top end refresh and tossed on a set of x-heads. I had over heating issues all summer, tossed in a new 3 core rad, new fans and multiple thermostats. Still had issues. I just pulled this engine apart and found that the rings were cooked. before ordering new rings I wanted to double check the piston size and found that they were at 4.160..... IS THIS MY OVER HEATING ISSUES???? CAN THS ENGINE OPPERATE AS A DRIVER BORED THIS MUCH??????
to top it all off there is a little pitting in one cylinder. I don't think its enough to cause problems but with the size of the bore I'm guess they could not go any farther to get the pitting out.

340 block cylinder.jpg