Mixing and Matching Steering Parts

Ahhhh, yes! You deviate from factory stuff and things start to get tricky!
The drum brake "knuckle" has smaller holes to mount the lower ball joint/steering arm. The taper on the ends for the tie rods are the same from 63 to 76. The lower ball joint stud that fits through the lower control arm also uses the same size and taper.
If you intend to retain the '72 knuckle, you CAN drill the knuckle holes oversized to accomodate the 73-76 lower ball joint. Personally, I'd be inclined to keep the 1972 and older stuff separate from the 73-76 parts. I convert all my pre 73 cars to the 73-76 steering linkage. The parts seem to be more common and the older style makes it difficult to remove the oil pan without lifting the engine with a hoist.