DTG,
The OEM part info identifies that unit as for a 1966 C60 series truck. I don't think it is compatible. Also, you may want to note that the listing is for a rebuild and return to you of an existing unit, not an outright sale being offered.
I think your better option is to have your existing one rebuilt by one of the known providers mentioned by Mike B and Otto above.
Since your "part" has been identified, suggest further discussion on this "brake" topic continue in your
Big Bolts thread.
That is where you will find the above mentioned diagrams and pictures I promised shortly.

See you over in "Big Bolts"!

Dan