Cock the shutter on the camera body. The mirror box should be uncharged before installation.

Twist the three motor drive wires together to easily insert them through the bottom of the camera.

Carefully track wire routing during installation. Make sure nothing is getting pinched and that all wires are accessible for resoldering.

Once the front block is in place, check the mechanical speeds of the shutter before completing the reassembly. The mirror and shutter should function normally.