Like Swartlkk said. The flattening of the old weakened springs under load caused the shackle to rotate towards the back of the truck. Therefore; what needs to happen is rotate the shackle back towards the front of the truck until the holes line up. Or install front end of spring first, raise rear of spring to proper height and rotate shackle forward until you can install rear bolt.

 

That was it! I didn't even think about loosening the shackles! So I loosened it up and sure enough in they went. So I have another little think that I noticed...that probably isn't important...but I just want to make sure. The old spring had a bolt in the center that dropped through the hole on that base that the U-bolts go through. The new leaf has that bolt too, but its not long enough to go through. Should I worry about this? I'm thinking the U-bolts are all I need right? that little bolt doesn't even have a nut. Also, do I need to tighten anything here to a specific torque....or am I just tightening as hard as I can? Thanks guys....I couldn't do this without you!

 

Sounds like your replacement springs have a rivet in the middle (a solid steel one) holding the spring pack together. This just gets put into the hole in the center of the perch.

As far as torque values...
Leaf Spring to Front Bracket Nut 89 ft.lb
Leaf Spring U-bolt Nuts 74 ft.lb
Spring Shackle to Frame Nut 89 ft.lb
Spring Shackle to Leaf Spring Nut 89 ft.lb

 

that bolt is just a guide to get it lined up on the axle