Vorshlag has been making spherical shock mounts for many years, for a variety of chassis: Corvette, many BMW applications, NA/NB Miata, 86 and more. These rear mounts are specifically for the the 2015-19 Mustang "S550" chassis are made in house here at Vorshlag and feature the same over-sized spherical bearing you'll find in our camber plates. These shock mounts are big, beefy, and as strong as a tank. Removing the stock rubber top mounts and replacing them with spherical top mounts will improve suspension articulation and movement.
Even when these OEM rubber shock mounts (above) are brand new they have a lot of slop from the rubber bushing. This rubber will compress and slow down damper reactions to vertical inputs in the suspension. Going to a spherical mount fixes all of that.
More importantly, the OEM shock mount's rubber bushing is held into the aluminum mount by a steel washer, which is crimped into the upper edge of the casting (visible above). This is prone to failure, especially when you convert the rear to a coilover shock. It acts like a "fuse" and when higher suspension loads pass through this it can "pop"...
This is because the OEM mount is made to only see damper loads, but when you move the spring to the shock the mount then sees the full suspension loads, which are an order of magnitude higher. Replacing the "fused" stock mounts with a properly engineered, spherical top mount adds real reliability to a coilover rear setup (see above).
Another feature of the Vorshlag shock mount design is the dual mounting positions. The "top" position shown above adds 1.5" of additional shock stroke, which is helpful when using coilover rear shocks made to the stock length on a lowered car. Most users should mount these as shown, which will gain much needed "bump" travel in the rear dampers. The "lower" holes match the OEM position and can be used for stock ride height setups (which are very rare).
We developed these mounts after noticing that many shocks can bottom out (run out of "bump" travel) when using a spherical rear shock mount made to match the OEM heights. For a lowered S550 on coilovers that sees road course, autocross use, or even street use, the additional bump travel is very worthwhile. After street and track testing this solution on our 2018 Mustang GT we are very happy with the design. We strongly recommend these when using any coilover rear shocks on the S550 chassis.
UPPER STEM DIAMETER: These shock mounts are designed to work with virtually any rear shock that is made for the S550 rear (that isn't an "eye" style upper). We use different upper and lower bushings (spool pieces) to adapt the big 3/4" ID of our spherical bearing to the shaft sizes of the very top of the rear shock. YOU have to tell us how to build your shock mount assembly by picking the proper upper stem diameter of your rear shocks at the drop down menu below.
The part we need to know from you is the very top - which will have a 10mm/M10 threaded or a 12mm/M12 threaded upper shaft stem. Typically an OEM or non-adjustable shock has a 10mm shaft and an adjustable aftermarket shock has a 12mm shaft. The shock mount sits on the shoulder or step where it goes from the big diameter and necks down to the small upper stem diameter. See the images below for a better explanation. If you are unsure about shock shaft upper stem option to choose, please email or call us.
Radial Bearing Spring Perch: As an option, Vorshlag's spherical upper shock mounts can be configured with a spring perch complete with radial bearings and all appropriate spools or spacers needed to match your suspension. This will only be necessary if you have a non-inverted coilover rear shock, which uses an upper spring perch at the top of the rear shock. We can make these to fit 2.25", 60mm, or 2.5" ID coilover springs.
Very similar to our camber plates, the radial bearing spring perches help in eliminating spring bind. Many people will try and use thin Torrington bearings, but they are just not up to the task of street driving, never mind hard core track use. Call if you have any questions about this option - this is not needed on many coilover S550 rear spring setups (some MCS dampers use an inverted rear with perches at the other end)