Most 67s didnt really have a PCV system. That was the last year of the draft tube. There should just be a rubber hose basically coming off that port on the block and running down. Under the intake manifold should be a oil separator canister that is supposed to keep the blow by down. That can could be full or missing if you have not pulled the intake on it.
If you want a PCV system, look at how the L79 (327ci/350hp) or the 67 Z/28 302s were ran. You need an Oil fill tube with the provision for the PCV valve, that is then routed into the carb base (on a factory L79 Holley its on the base on the passenger side at the rear. Then they had a special tube that fits into where that road draft tube is on your block and it routed it into the air cleaner base. They dont make the bent metal tube any more but you could route a rubber hose to the air cleaner base off that fitting in the block.