The weight box looks homemade, the real ones are shorter and longer. If your going to add a creeper I would also add a new driveshaft, clutch and throwout bearing, these items will definitely have some wear on a machine that old. We have a member here that makes shafts for a very reasonable price, his screen name is Jeff in Pa. Here's a link to his thread.
http://www.onlycubcadets.net/forum/s...ad.php?t=20875