I just did the opposite today. I'm curious, did your 4/1s look like this? Mine had almost 2" more arc than the 3/1s - note the center bolt, looks hokey to meI got my 4+1's in the truck this morning, and I did put them on a shackle flip at the same time but minus everything else I did the 4+1's gave me a net 2" of lift over my old worn out 3+1's.
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