Old Race 340 Teardown
I bought a 360 of similar vintage that was built by someone who ended up being quite big in Slant 6 racing apparently. it was obvious that they spent too much time reading about rod ratio, as it had 6.625" long BME aluminium rods in it. BME rods from the early 80's aren't as durable as what is available now, the set in this engine hadn't done a bunch of work, but the big ends on two had started to distort. The bolts should thread in and easily, if they are starting to bind up slightly, they are on their way out.
There was some cool stuff in the engine, but it was very much outdated. I ended up parting it out. The rods I sold individually, people buy them for man caves or steering column clamps for hot rods etc.
Best of luck with your project.