I want to lower my 56 3100, say 3 inches in front 5 in back. I dont want to go all out with an IFS in front there are a few vendors who sell a new axle for the front that lowers it 3 inches. I want to keep the original rear end in this truck. Is there a way to lower the rear (via blocks) or would I have to upgrade to a more modern rear end with different leaf springs?