a PCV will eliminate the need for the road draft tube, and you won't have any problems because of the change, no telling if it will totally eliminate any smells .... yes that oil pressure behavior sounds fine, good pump and tight engine, about what mine does with ~20,000 on a full rebuild .... sounds like someone has done some mix-n-match on that engine, the tube at the front of the intake should have a breather cap on it and that's the oil fill point, the early 283 had no breathers or caps on the valve covers, and it wouldn't be a bad idea to have non-vented caps on both valve covers, the PCV will draw air in from there
Bill
