Project FD RX7 Restomod: Part 16 – Installing the Ronin Ford 8.8 IRS Mount Kit using DSS Axles

FD RX-7 Ronin Speedworks Ford Explorer 8.8 SwapWe busted out the TIG welder and installed the Ronin Speedworks Ford 8.8” IRS Mounting Kit.  Then we shipped off the subframe to get powder coated before installing the show car quality rear end into our FD with the new DriveShaft Shop “Direct-Fit” Axles.

Installing the Ronin Speedworks Ford 8.8 IRS Mount Kit might seem intimidating, but it was actually a lot easier than I originally thought.  If you have a MIG welder, angle grinder, and know how to use a level; or know someone who can TIG weld and has more grinding tools, the installation process was very straight-forward with easy-to-follow directions.  This further reinforces the argument that I made in PART 14:

“As soon as you need to replace the OEM limited slip differential with an expensive aftermarket clutch-type LSD, the Ford Explorer 8.8” swap becomes the better solution”

Ronin Speedworks FD RX-7 Ford 8.8 IRS Mounting ONLY KitThe Ronin Speedworks Ford 8.8 IRS Mounting ONLY kit includes the (weld-in) Front Mount Support Bridge, the (bolt-in) Rear Mount Diff Ring Cradle, all mounting hardware, RTV silicon (for rear cover installation sealing), and four subframe reinforcement plates that are optional to install if further strengthening the subframe is desired.

We chose the Mounting ONLY kit, which does not include their axle bars (shafts) and requires using the FD outer CV joint and sourcing 2007-2010 Explorer inner stub axles/CV joints.  Instead, we will be using Driveshaft Shop’s “Direct-Fit” bolt-in axles.

Ronin Speedworks FD Ford 8.8 IRS Front Mount Support BridgeThe Front Mount Support Bridge needs to be welded into the stock subframe and not only contains the two front mounting locations for the Ford Explorer differential, but it greatly stiffens up the entire subframe.

Ronin FD 8.8 Swap WeldsThe TIG welds on the Support Bridge were very nice.

Ronin Speedworks FD RX7 Ford 8.8 IRS diff mountThe Rear Mount Diff Ring Cradle is sandwiched between the diff housing and the rear cover.  The mounting ears bolt in to the factory locations on the rear subframe.


  1. This is vastly superior to any other 8.8 conversion I have seen for this car. Now to convince Jeff to do this to Project V8 FD!

  2. Great write-up and an impressive kit.
    Although, it seems the support bridge could be easily revisioned to be at least half an inch lower so it wouldn’t necessitate beating up your pristine RX-7-s body.

  3. Damn, great progress. 🙂

    still loving the fact that this went from rest-mod to restless-mod.
    been following from the beginning.

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