1965 dodge dart 2 door : Issue with super stock leaf springs

So for a couple of years ive been buying a part or parts here and there for my 65 dodge dart . These parts are A-body = 8-3/4 housing , 489 case , polyurethane bushings. The super stock leaf springs, stock Abody shackles and front hangers and rear mounting brackets for shackles came from Mancini racing . well past few days I've been bolting the parts together . Got the front hangers on with bolts just screwed on but not tightened and the same for the shackles. the rear of the leaf springs does not match / line up to slide the bolt in on the bottom of the shackle in to the leaf spring ?? someone told me I would have to have the weight of the car pressing down on the tires to flex the leaf springs out ? but that would just push the back part of the springs up to the floor of the trunk. the shakles are angled forward facing the end of the springs but is 1/2" - 1" too short ?
I can send pics if need be
That happened when I installed the springs on my 66 Dart. I hooked up the front and the rear shackles were facing forward. I got a long pry bar and inverted the shackles. I don't know what the trick is to do it different. May be install the rear first then weight the springs to install the front? Worth a try I guess.