Should be the same, I just went out to the carport and measured mine. At wheel center level it is 2-1/2" front and back, Maybe yours are in backwards.

I still don't see how you centered the axle on the springs. You don't have a hole in the perch, does the center bolt protrude all the way through the shims and into a hole in the traction bar?

The mono leaf rubber upper spring pads had some 'speed bump' kinda humps in them that rested in the grooves in the perch and the center bolt fit into the hole in the pad. That kept the springs in position untill the bottom plate was tightened in place with the center bolt protroding into the hole in the bottom plate. Those mono leaf pads are only 2-1/4" wide for the mono leaf spring, multi leafs are 2-1/2'. Do you have the single or multi leaf pads or any pad at all?

Man, if you lived close we could go over and help you out. Bit far for a sunday afternoon wrenching session.