No drawings, but I just did this today for a YJ spring over.
1/4 inch plate, length of your choice, but somewhere between 6 and 7 inches. Mark a center and drill to the spring center pin size. Mark for your U-bolts center to center, and drill.
Drawing would be different depending on the diameter of the u-bols used, but the springs are 2.5 inches wide.
Pretty easy really.