72 K20 arc length

[lutjanid]

Does anybody know what the factory arc length is for front and rear leaf springs with factory heavy springs option on both? I need to replace all the leaves and would like to lift the truck 1-2". I have the feeling that new springs will probably lift it that much, just from sag. If not, then I can order +2 springs. But, I don't want to end up with 4+ inches of lift in the end.