I wanted to add a direct drive genuine e3d Titan extruder to my Ender Max but wanted to keep the stock heatsink and fan shroud (I've upgraded the heat break to the Slice Engineering Copperhead) and had difficulty finding much to suit the Ender Max as its X plate and gantry are the same as the CR-10V2/3 rather than a standard Ender.
I basically moved the motor mount another half motor size further out to cater for a standard Titan (mirror version would probably work with the original mount).
You need a length of PFTE tubing to connect the stock heatsink coupler to the titan bowden coupler (yes its at a slight angle, the positioning isn't perfect, but it seems to work cleanly).
As in the original, you'll need two extended screws to replace the 2 short M3 screws that attack the fan shroud - the thin wings that hold the plate on should slip under the new mount.
You'll also need an extended stepper motor cable for the extruder motor.
e-steps for me with Creality stock motor worked out at 393 - different motors/clones might vary.
If you print it at an angle with some supports you should be able to get away without needing supports all over.

Prusa

I3 MK3S

No

Yes

0.2mm

25%