Available in OEM and aftermarket at CruiserTeq
https://cruiserteq.com/drive-line-bolt-hardware-kit-11mm-bolt-washer-nut-kit-fits-1974-newer-applications-uj90105kit/
Check if you have 10 or 11mm hardware as '74 is a transition year. My '74 model year (10/73 build) originally had 10mm hardware.