Ender 3 / 3 Pro with Linear Rails dual Z mechanical G34 stoppers

These blocks will stop the x axis gantry at a precise height to make the Marlin "Mechanical G34" work with linear rails

You will need to activate Mechanical Gantry Calibration in Marlin, by uncommenting #define MECHANICAL_GANTRY_CALIBRATION in configuration_adv.h

This precise block is made for the following configuration:
#define GANTRY_CALIBRATION_EXTRA_HEIGHT      15
#define Z_MAX_POS             210 (configuration.h)

I know that this is reducing the available printing volume but I personally never printed such tall items that i don't feel the problem.
Also being that conservative avoid squishing the bowden tube.

Still, if you feel the need to have it smaller, contact me or i will eventually upload the fusion360 file.

Print 2, mount each one right above the Z linear rails, use a V-slot mount nut.

You better measure YOUR Z_MAX_POS height carefully before running it, use your head. I am not responsible if YOU damage your hardware/printer.