If you run drop spindles, you have to convert to disks up front. There are no drop drum spindles. If you don't want to convert, then you can only go up to 2" lower up front with springs without making any modifications. As bs46488 pointed out, a 4" drop spring on an otherwise stock truck results in a terrible ride. That doesn't mean it can't be done, however. I have 4" springs on mine with the original front drum/spindle (although I do plan to upgrade to drop spindles soon) and the ride is very good. I did have to cut the bump stop mounts out, run the caster mod (
here), flip the outer tie rods to the bottom of the spindles, and of course get an alignment, but it does ride nice now
.