Youll just have to clearance the bottom of the reduction housing to clear our bigger 4.70 counter gear. 

Don't forget about the sides of the reduction housing to clear our larger low speed gear, which is a required 4.70:1 modification to approximately 95% of all reduction housings Toyota produced.
And the high-netural-low shift fork and the 2WD-4WD shift head since it's a top shift style case.

TaroVr6, These mods we are discussing may be seen through the following two links...
How to Clearance your Reduction Housing
How to Clearance your Shift Forks
...and are outlined in our Online 4.70:1 Installer.

Additionally, if your old forks are badly worn out (this is a rare symptom) or you are missing core pieces, we offer our own Shift Forks that are designed for our 4.70:1 gears (so no clearancing is required). Links to these products:

Shift Kit, High/Low

Shift Kit, 2WD/4WD

Sorry for smothering ya, I'm just having some fun with Goldrush

Regards,
BigMike