1963- 250 hp pvc?

What you have now is essentially the same thing, I think... a hose from a hole on the rear top of the block to a one-way valve at an elbow that enters the rear base of the carb (crankcase ventilation). The oil breather cap allows air to flow into the block, through it, and out the rear hole. If you have a lot of blowby, I suppose crankcase vapors could be forced out of the oil filler, but that means you've got a serious need for an engine rebuild.

Is that what you have? I'm not sure why you'd want to change it. Other years/models take the crankcase vapor from a grommeted hole in a valve cover or a nipple on the oil filler tube. They accomplish the same thing, SFAIK.

Is this "one-way valve " the equivalent of a PVC? We are doing an engine+carb. rebuild and my mechanic was pondering the change-over if there is an advantage. I am replacing the hose/grommet assmbly. for the breather and it also shows a "PCV ADAPTER - ELBOW IN BACK OF CARBURETOR" but it doesn't show an actual valve. It only shows PVC for F.I. engines , as I read it. (Corvette Central online parts diagram /part #352033). Thanx- lib

Check the diagram in the upper right corner of this document page:

After further review, I am going to stick with the original system. Thanx for the info-lib