This kit is designed to adapt the frame of a 73-87 C10 pickup (Long or Short Bed) to accept a 12-21 Model S or 15-21 Model X Tesla rear subframe/motor assembly. The kit is pre-engineered to rigidly mount the applicable Tesla subframe in the correct position on the truck frame to achieve proper suspension geometry while substantially increasing the rigidity of the truck frame. This kit also incorporates upper coil over shock mounts to pair with Holley Part Number HEV001-001 to successfully convert the stock Tesla coil over suspension to an aftermarket coil over shock system that is positioned lower to allow a clean fit into the swap truck without having to clearance any of the truck bed. Depending on the coil over shocks used this kit will accommodate a 4-6 inch drop from factory ride height in the rear of vehicle so it is advisable to also lower the front of the vehicle. An excellent addition to this kit is the SpeedMax kits for the front of the vehicle offered by Detroit Speed. Note: This kit requires notching of the truck frame and installs very similarly to a typical C-notch kit. It is also required to drill additional holes in the frame to rigidly bolt the subframe mounts to the frame. While welding the frame mounts to the truck frame is not required it is possible to further strengthen the assembly. Depending on the front-end conditions of the vehicle and the weight balance front to rear it is recommended to run 200 lb./in to 300 lb./in coil springs with the coil over shocks (Not Provided). Coil over shock/spring assemblies should be standard 14" x 2.5" size. Wheel recommendations: The Tesla suspension has a wider track width than the O.E. truck track width does. In order to fit wheels and tires in the fender wells without modifications we recommend using 10" wide wheels with an 8" backspace measurement to optimize clearance with the outer fender and the frame rail on the inner side. Wider wheels will not fit without modification. If narrower wheels are chosen the backspace should be calculated in a fashion that keeps the position of the outer face of the wheel in the same location (width should be removed from the inside of the wheel).