The fittings you need are on Ebay, but the PC Patrol will delete a link if I list one. Search Ebay Motors for "oil pressure line kit". The fitting you need is an adapter included in the "63-67 Corvette" oil line kit. It screws into a 1/8" pipe female thread and accepts the crimped-on nut that's currently on your oil line. If the nut on your line is bad, the kit contains two new ones, and a piece of 1/8" copper line. That adapter is a very scarce fitting, so don't lose it this time!
Jerry