NOTE : it is not legal for on road use and is not something you can unbolt and bolt the stock stuff on.
Cut old box mounting gear off
Clean and prep chassis
Dummy box with steering shaft in place to check everything, locate as close to rad support as you can get it
dummy fit new plates, mark them, drill crush tube holes and fit them, tack the ifs box mounting plates on, temporarily mount box to mounts and check nothing will bind up steering shaft wise etc.
My box is mounted a little on the piss. to give me more room from pitman arm to leaf pack as mine isn't lifted much and have no intentions of doing so.
Once everything is right, remove box etc, weld on the plates, we welded the crush tubes also, paint everything.
You'll need to fit the steering shaft onto the box's spline before mounting the box or its a PITA to get on.
When putting everything back together you need to align the centre of the boxs movement to the wheels being in the straight position, not doing so will not give u 50 left turn 50 right turn.
Then either fit a double arm to the pass side knuckle, or hi steer arm, and purchase relevant rods, tierods etc.
Take it for a wheel alignment.
thats the basic jist of it, but im sure its been explained in greater detail somewhere on here before.
I have pics of the steps and better pics that show everything although i seem to have misplaced them ahah
80 series pitman arm
this photo is upside down but gives you an idea of mounting location that we put it in and works fine.