motor fixation screw length

[Didier Molard]

Hello.
Changing from "standard" to "red boxes" electronics / motors, i came across issu on main motor length.
They are said to be 45mm, but at that length, they do not protrude the motor flanges.
i found some 50mm long one, and they go through by a little 5mm (nearly the same than it was on old motor fixation)
will it be ok, or do i better have to use 55 mm long one (assuming the threads in the motor block will be ok too)?
as on old engine the centering area was bearing part of the stress in addition of the screw

Do someone having swapped form old to new motors got same issue ?

Regards
Didier