I upgraded my Anet A8/Prusa clone's extruder with an E3D Titan Aero. This bracket uses 46mm X axis guide rod spacing and 4 8mm bearing guide blocks.
12 M4X12 SHCS
3 M4X20 SHCS and nuts
If you plan to mount a BLTouch:
1 M3X16 SHCS and nut
1 M3X20 SHCS and nut
When assembling the carriage to the guide blocks note that the bottom left guide block only uses 2 of the 4 bolt hole locations. The top right and bottom left are left empty to make room for the filament tension knob and the aux fan.