you can add dead leaves to the bottom of your current spring pack, like (2) - 1/2" leaves bolted in would do the trick! They dont have to be long, maybe like 1 ft and step it down on the other to maybe like 8" to keep the taper look to your pack
trust me, dead leaves are the key, dont stack. the bolt running thru the entire pack keeps the integrity of the spring and protects those stacked blocks from rolling off one another.
Dead springs can be made from old leaf springs or can be built at a local spring shop.
I reccomend them over stacking, even if it is a one inch block. I added 1.5" to my buddies front spring packs in his 2004 f350 and they worked perfect.