So I agree that the PCV may be the issue, but its not likely. Like Matter stated the PCV ports/locations can be left open, the engine will run the same. This is not true for the port on the carb spacer that the PCV hose connects to. If this port is left open you will have a vacuum leak which will cause the engine to run rough. Was the port on the carb spacer plugged or left open?It doesn't matter what side the pvc valve is on, and the hose from the pcv goes to the base of the carb as it was. The other side can be open as it was but is more desirable to have the hose on that side go to the air cleaner so it is drawing in filtered air.
There are many possible causes for the issues you are experiencing. Likewise a lot of good information has been listed above. Be sure to diagnose the issue first. Do NOT throw parts at the problem hoping for a solution, this just causes aggravation. Additionally when the time comes only change one part at a time this way you know for sure what fixed the problem. This will allow you to expand your knowledge and will make diagnosing issues easier in the future.
The chances of this being your timing chain are very unlikely. Perform a compression test first. Yes a replacement timing chain is cheaper than a compression tester but like I stated above knowledge is power. Additionally what happens the next time you have engine troubles?
Keep in mind a timing chain replacement requires new oil, coolant, gaskets, and a harmonic balancer puller at the minimum assuming you have basic hand tools. This all adds up and the more you spend the more aggravating the hobby becomes...
Just food for thought.