Re: '62 with Road Draft Tube
I don't have a Buick (1964 Ford Galaxie), but I highly recommend that you switch to a PCV system. What you are experiencing is fairly common with road draft tubes. Also, if there is nothing to block oil, you will probably find the underside of your car covered in oil.
In 1963, the Ford 390 engines used a road draft tube except in California, which required a PCV valve. In 1964, the PCV system was standard nation wide.I would recommend that you just go ahead and install the 1963 Buick system for that engine if it is available. You will know it works and you don't have to spend time rigging up things. Also, if you go with the PCV, you only need ONE vent to supply fresh air to the system. A PCV system is basically a controlled vacuum leak. You only want one path in and one path out of the engine for air and fumes to flow. To add a second vent will break that vacuum path and increase the risk of oil blowing out of the vent caps.
Good luck and let us know how things work out.