Hubs for a 66 Cuda.

Junkyard or maybe someone has a stash somewhere of NOS ones you could pay thru the nose for.

I'd put new bearings in your hubs if they are ok and run that.

As for how to...

http://www.mymopar.com/index.php?pid=109

they have the factory service manual available for free.

Proportioning valve, yes.

They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.