The LS motor make substantially more power than the little 13B, meaning the rest of the drivetrain needs to be upgraded to get all that sweet pow-pow to the ground.  One of the weaker links on the NA FC is the diff and axles, so we’re going Ford 8.8 IRS mounted using the Ronin Speedworks mount kit.  But before installing this kit, we have to remove the entire rear end.

This post is basically a reiteration of this thread on RX7Club: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/write-up-removing-rear-sub-frame-802796/

I found that thread to be extremely helpful, but I’ll still document the steps I took for science.

The car was already on jack stands the first thing I did was support the differential using my handy Harbor Freight transmission jack.  Next, simply take off the brake calipers and support them on the springs with bungee cord or anything really. 

Now time to get under the car.  There are two front mounts for the rear subframe.  Use a 17mm and 14mm socket to get them off.  Make sure to wear a mask and eye pro, because there is a ton of nastiness that got in there over the years. 

After that, remove the diff ear mounts (2) using a 17mm socket. 

Next, remove the sway bar end links with a 14mm socket and 14mm wrench (nut and bolt kinda thing) on each side.  While you’re there, go ahead and remove the rear struts from the hub with a 17mm socket. 

Lastly, there is a vertical link support on the driver side of the diff.  This one was a bit tough for me to get out.  It’s a 17mm bolt and nut, but the bolt just did not want to come out! I used an oversized socket with a vice to press the bolt out.  I feel like putting this back in will be no fun..thats a future Andrew problem.  

Once everything was removed, I got a breaker bar to serve as a pry bar and wedged it between the frame and front of the rear subframe.  You want to essentially pry the subframe from the front mounts, with a bit of  force it’ll fall kind of easily. 

Once it was off the car,  I lowered the trans jack and pulled it from under the car! Like the thread says on RX7Club, time to grab a beer!