Lowering 70 C10 long bed ?

[squirrel]

If I want to lower my 70 3" in front and 5" in rear, can I get away with just doing springs and shocks or do I need anything else. Thought I read somewhere if you go 5 or more you needed something else. Forgot what it was. Any help would be appreciated. Here is a picture of what Im working with. It is sitting with a 2" drop in the rear now to make it level. Thanks again for any input.