Help the Dummy - new rear leaf & shackle

Don't drive it like that. Sometimes with new springs the arc is stiff and short enough to cause what we see here. Jack it up by the body, unhook the shackle, then put a block of wood between the back of the spring and the body above. Then slowly let the jack down and the weight of the car on the block will push the spring down and back to where you can hook the shackle in the correct position. Just be very careful as you do it because springs releasing energy at unexpected times can do bad things to human bodies.