Steve,
Just to complicate your options: does your valve cover have four slits/slots in the top (as was found on 54/55-1st non-PCV engines)?
If you have the slits, you can use the vented oil filler cap or the original non-vented oil filler cap but no PCV system (the slits in the valve cover and/or the vented oil filler cap do not allow the PCV system to operate properly).
If you do not have the slits:
- you should use a vented oil filler cap with no PCV;
or,
- you should use a non-vented cap with a PCV system.
As doc41 suggested, do what suits you. If you want an opinion about original appearance:
- Use an original PCV set-up for 54/55-1st (hosed-draft tube, hosed air-cleaner/valve-cover, and non-vented oil filler cap);
or,
- Use an original non-PCV set-up (non-hosed draft tube, non-tubed oil-bath air cleaner or wire-mesh air cleaner, and matched valve cover and oil filler cap.
Nothing like a clear, concise answer, right?
Tim
