Xhimsa12x, just wanted to let you know that no, springs are not just springs, as you've asked several times. Spring specs vary widely so they can accommodate many applications.
As you have discovered already, auto suspension springs come in two types, coil and leaf.
Coils vary in wire diameter, overall diameter, free height, fixed or progressive rate and how the ends are finished (open, closed, ground).
Leafs vary in number of leafs, free height, eye to eye length, single or two stage packs, material thickness and width, leaf end styles, eye wrap styles, bushing types and a few other small things.
Have a look at this chart
Cruiser Outfitters
You can compare the 881/2/3's to the 885's and see whats going on. As other have pointed out, the free height of the 885's is going to be the biggest issue.