Lowering my 71 c-10 with leaf spring rear end

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I want to lower my 71 c-10, but it has a leaf spring rear and the only thing Ive found so far is to buy new springs from CPP. but tht would set me back $400.Id like to drop the rear 4". Has anybody else done this and if so what did you use? Also someone told me that its rare to have leaf springs on a c-10 2wd, Is this true? Thanks for any help