[chrs1961815]

In an ideal world, there should be no leaks but after chasing mine down and not fixing it, I have come to the conclusion that all Model A's leak a little.

Your rear main leak can be caused by many things - I assume your gaskets are all relatively new and hopefully you have the gasket between the flywheel housing and block. That is sometimes left out which causes a bad rear main leak.

I would figure out where the knock is coming from - if not from the crankshaft, it could be worn wrist pin bushings. But I would doubt that if the cylinders had very little wear.