Richard,
Any idea what (over)size you are after? David and Mike are correct. your 216 originally had poured babbitt conrod bearings. .20 conrods are available NOS here in Holland, I think from LWD and another source.
Main bearings....sets are offered on Ebay from time to time, but some sizes are more difficult to find than others. If you do go Ebay, make sure you get a set for early 216's as later ones used a different size.
Main bearings on the Chevrolet G508 (1,5ton with the Jimmy nose) are the same as Canadian 216. Jeep-Dodge-GMC in France have some NOS sets available.....but check part numbers to be sure if they are the correct ones.
https://jeep-dodge-gmc.com/smi/autres/CHEVROLET
LWD does have 1 of the Main bearings available NOS....the one with the "cheaks".....so, if you know which bearing causes the knocking.....
https://www.lwdparts.com/product/bea...haft-rear-030/
Alex