If you plan to lower the rear some too, I would buy the 2 inch lowered springs. Also, almost without exception the people I have heard of that bought 5 leaf springs for other than a station wagon complained about the harsh ride. It I bought new rears, they would be 4 leaf.
I'm running 4 leafs on the rear of my '57 Hardtop. They dropped it about 2 inches and gives a great ride. the front of mine is dropped 3 inches. www.picturetrail.com/starcitygene under "My Toys" (#2, I think).
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