In the Catalina 350, Catalina 380, Catalina 387, Catalina 400, Catalina 42, and Catalina 440 mastheads there is a pin along with Delrin bushings that support the sheaves. This new kit doesn't require the bushings, but rather the sheaves are supported by the pins only. There are two sheaves forward and two sheaves aft.

On some mastheads, like the Catalina 34 and 36 rigs, a hollow tube was used as the axle for the sheaves in lieu of the pin and bushings. If that is the case for your masthead, then reuse those tubes, typically a 22 mm outside diameter, and order the replacement ball bearing sheaves by themselves, part Z1971.

Sheaves (4 included):
• Outside diameter: 85 mm (~3 3/8")
• Inside diameter: 12.5 mm (~1/2")
• Width: 15 mm (5/8")
• Line diameter: 13 mm (~1/2")

Axle pins (2 included):
Outside diameter: 12 mm (~1/2")
Length: 50.5 mm (~2")