executable-chmod

executable-chmod is a variable defined in `executable.el'.
Its value is

73

Documentation:
After saving, if the file is not executable, set this mode.
This mode passed to `set-file-modes' is taken absolutely when negative, or
relative to the files existing modes. Do nothing if this is nil.
Typical values are 73 (+x) or -493 (rwxr-xr-x).

You can customize this variable.