Like @mdc and @gerard soriano , I bought a Predator 314-2 shaft and it fits perfectly on my 1985 Joss. IIRC, OB shafts also fit my Joss. I still prefer the Joss shafts, but that’s not your question.
Where you might have issues is hoping to use older, custom 5/16x14 shafts. For many, the...