So I got a set of free F-150 rear springs at work today. They are the same width as an XJ. I grabbed the 3rd & 4th spring, as the 3rd was under 42 inches length & I was thinking full length aal. But they got one hell of an arch in them. I just want to get rid of the 2 inch block the P/O had in and get 3 inches. My ? is, has anyone done this? Or is it trial and error till I get the lift I want?