In the late 50s and early 60s Chevy used a combination oil filler and breather tube on the front of the intake manifold. If you like the look consider machining your intake for one. Not all intakes are machinable. Look for one with a round boss on the front.

The Moon valve covers on my roadster have three (1+2) ports machined in. One is for the oil filler. Two (one in each coner) will take a breather or a PVC.

You can feed oil through a PVC port. But it is real hard and real messy out of the quart bottle.