2018-04-02 - Updated Version: I Quickly Realised A Few Problems With The First Design And Have Since Updated The Following:

Filament Feed Alignment
Spring Tension Placement - Old Version Caused The Finger The Wander Out Of Alignment
Stronger Frame

New Version Has Been Working Better Than Expected, So Much So I Might Upgrade The Printer Further With A Heat Bed.

For Those, Like Me, That Still Have An Old Cubify Cube Gen 2 Lying Around, Here Is An Upgrade To To Get Rid Of The Default Print Head Assembly And Replace It With A E3D V6 Setup. This Upgrade Came After I Destroyed The Old Main Board On Purpose And Replaced It With A Tevo Tarantula Motherboard Mks Base V1.4 Since It Can Handle A 24V Supply. This Is Designed To Re-Use The Existing Stepper With The Drive Gear Fitted In Place. The Overall Design Would Be Better With A New Stepper Motor, As The Gear Is A Little Close To The Stepper. What You Will Need

E3D V6 Hotend Assembly
One Stiff Spring. I Used The Springs That Came With The Bed Leveling Kits
~~3X M3 30Mm Bolts~~
~~4X M3 20Mm Bolts~~
~~7X M3 Nuts~~
One U -Groove Ball Bearing And Appropriate Screw To Keep In Place : U604Zz 4X13X4

Edit: Old Parts List, Just Get A Few M3 40Mm Bolts,Nuts And Washers. That And One M4 40Mm Bolt, Nut And Washer For The Spring At The Rear Of The Finger. And One M4 20Mm Hex Head Bolt + Nut + Washer For The U-Groove Bearing 2020-02-28 Update: Buddybu Was Kind Enough To Play Around With The Print. Please See His Comments And Attached Picture. The Bottom Two Screws Should Be 25Mm M3 Assembly Assembly Is Easy. Strip The Old Cube Head Entirely, Removing The Metal Frame That The Stepper Motor Is Bolted To. Print All Of The Parts And Assemble As Such:

Main Body To The Cube Print Head
Insert The Support Plate
Insert The Rigid Plate
Insert The E3D Cooling Tower
Bolt The Stepper In Place, Through The Main Body, Support And Rigid Plate
Assemble The Bearing Unto The Finger And Affix To The Main Body
Insert The Spring At The Top - I Used An 20Mm Bolt To Keep The Spring In Place. It Sits Snugly On Top Of An M3 Hex Nut.

For Cooling I Printed One Of These E3D V6 Hotend - 40Mm Fan Duct As I Had A 24V 40Mm Fan Spare.

Found 1 3D-models for “cube gen 2” across many websites

Cube Gen 2 E3D (v2)