PART NO.  SPL.PAGE  DESCRIPTION                                                           
52K485    15.F.1    Stud - front cover (gearbox) (7) - changed to 53K2172 Com.(G)A916
52K485    15s.F.1   Stud - front cover (gearbox) (7) - changed to 53K2172 Com.(G)A916
53K2172   15.F.1    Stud -front cover (7) (gearbox, 1500)  -Com.(G)A916 -(was 52K485)
53K2172   15s.F.1   Stud -front cover (7) (gearbox, 1500)  -Com.(G)A916 -(was 52K485)
53K2172   TC.F.1    Stud -front cover (7) -(gbx.casing, gearbox assy, Twin Cam)
53K2172   16.F.1    Stud -front cover (7) -(gbx.casing, gearbox assy, 1600)

52K485 - Stud -Stud for front cover (7) -(gearbox 1500, 1600, 1622, early 1800)
Length:1-5/8"
Top end thread: 5/16-24-UNF x 5/8"
Bottom end thread: 5/16-18-UNC x 15/32"

High Strength Stud

Part number was 52K485 for early 1500 gearbox.
Part number changed to 53K2172 for later gearboxes.