[ Ref. http://www.player-care.com/d-a_pulley.html ]

Interesting pictures; one can tell that the driveshaft pulley has
already been replaced with two modern pulleys.  The supply house
should be able to offer you one pulley designed for two belts, just
like the swollen one once was.  Calculating the diameter it should be
might take a bit.

David Dewey