Although it is not necessary to completely disassemble the rear strut housings to install the new shock assemblies I find it is a lot easier to do it on a bare housing without the lower control arm and brake components in the way
 

   Here is a typical 240Z rear strut housing.  Measure and mark the strut tube at about 5 ½ inches up from the bottom forging. (7 ½ inches for a 280Z)  We are going to use a chop saw to make the cut.  I do it in two steps, first cutting the tube just below the spring perch (just to get it out of the way) and then making the final cut.
 
 

  Here's what the strut housing looks like after it's been cut, bead blasted, primed and painted.

  Almost forgot to drill the bottom of the strut housing for access to the damping adjustment on the bottom of the shock. I use a ½ inch pilot drill and then a ¾ inch drill bit.

Here's the damping adjustment knob on the bottom of the shock. 15 steps provide a huge range of adjustment, turn it gently!

  Slide a piece of 5/16 fuel line over the knob so it can come out through the hole you drilled in the bottom of the strut housing. Retain it with a hose clamp. This will give you easy access to the adjustment.

  Here's the top of the shock with the camber plate components.  Refer to the instructions for mounting the camber plates.

CLICK HERE FOR THE CAMBER PLATE INSTALLATION GUIDE

We slid the adapter sleeve into place over the original strut tube, it needs to overlap by at least 1 inch and can overlap up to 2 inches.  I recommend that you trial fit everything before welding the sleeve to the strut tube (at red arrow). You can put everything together and put the car on it’s wheels ( before welding) to make sure the ride height is in the range of where you want it to be with room to adjust it both higher and lower.  The shock needs to be threaded into the sleeve at least 1 inch.  There is 4 inches of the thread inside the sleeve for wide range of adjustment.

Here is what a finished installation looks like on one of our ROAD RACE STRUT ASSEMBLIES.

Don’t forget we make a whole bunch of cool other parts for the rear suspension.

Now we're moving on to the front install.

  Strip everything off the original strut assembly.

Mark the strut tube approximately 1 ¼ inches up from the spindle forging.

Cut it off as shown (be sure to clean up the cut edge to avoid slicing your hands).

You will need to grind a notch in the sleeve so that it clears the hump in the spindle forging and allows the sleeve to slide all the way down as shown.

Weld the sleeve to the spindle

Now you are ready to reinstall the strut assembly.

Here are some photos of a completed install along with our FIVE LUG BIG BRAKE KIT with optional 6 piston calipers.

Works great with our BILLET FRONT LOWER CONTROL ARM!