Original files from Prusa have been used to create those parts. I copied them and increased the height by 2 mm. At the end, the whole Z-axis is lifted by 2 mm, too.
You have to replace the y-rod-holder, z-axis-bottom and z-axis-top parts. Dont forget to mirror parts!
Print with Prusas recommended settings for printer parts.
The author hasn't provided the model origin yet.