[mickmate]

Originals were set up a couple of different ways. Most used an intake breather cap/fill tube at the front of the manifold. Some had a gooseneck style breather at the back of the manifold. Street cars often had the style cap you show on one side with the other side valve cover plumbed to carb. Towards the end of production I believe they were using the PCV plates on the back of the manifold as OP has done.