The coilover crossmember end saddles need to be installed in a specific location, determined by measuring from the back edge of the saddle to the center of the leaf-spring shackle hole. The distance between the two needs to be exactly 16 3/8 inches. A diagram in the Heidts instructions clearly shows how the measurement is determined. Note here that the saddle is in place at the front of the photo while the measurement is being taken. With some cars, the saddle will need to be trimmed to clear the axle-snubber bracket because the placement of the snubber bracket on the framerails varies from car to car.