I'm running the xhd mopar springs,numbers you listed,they where about 1" to high for me, i drilled new holes in the front hanger,it dropped the body down approx 1", changed the pinion angle as well. Note,frt spring holes/bolt size on the mopar xhd springs are 5/8",orig springs are smaller,you'll need new bolts and enlarger factory hanger holes to fit.
Here's a couple of pic's,(car has 255-60-15 tires) , the one with out the stripe on the car is new xhd springs in factory hanger holes etc, second pic is with xhd springs and new holes drilled in front hanger. The springs have been in the car for awhile and havent sagged/changed height at all.
