The Rear Leaf Spring Assemblies are very common parts that need replacement on Mustangs. They are actually one of our best selling parts.
When these are replaced, the rear spring shackle kits always need replacement also. They are always rusty and the end of the rods almost always snap off when the lock nut is removed. Not to mention that the bushing are always shot.
We have some very nice rear spring shackle assemblies to offer for your vintage Mustang. The most common kit is our SU43. This kit, like all of our kits, will fit all Mustangs from 1964 1/2-73. It features 9/16 inch rods (not sure why Ford later went to the smaller 1/2 inch rods later.) This is our most popular and our recommended kit.
We now have two new shackle kits. One is an "offset" kit. The top image in this post show this kit. This style of rear spring shackle appeared on many Mustangs and Shelbys equipped with factory dual exhaust sometime in 1966. The configuration allows easier installation on the left side where the exhaust is close to the shackle. It was originally found only on the left side.
This is our SU435 kit. Keep in mind that this kit will fit either side. It is just easier to install.
If you would like to use it like the original 66-up cars with factory dual exhaust, you can use our new SU434 kit with it on the right side. Both of the SU434 and SU435 kits have the 1/2 inch rods.
I know that all of this seems a bit confusing, but keep in mind that all three of these kits will fit any 64 1/2-73 Mustang model. Let us know if you have any questions!