Here is a more accurate answer from AllJ's site .....
"KJ's ALL VARY in the ride height department. Some have saggy springs, some have stiffer springs. This is why you get KJ's sitting at all different ride heights from the factory. If you add a Daystar or other spacer lift, you are dependent on the condition of the factory springs. We have had KJ's come into the shop with such soft springs that they got over 4" of lift when lifted with a new front strut set. They didn't really get 4", they are just 2.5" over stock, and they were sagging 1.5" below stock. And that 2.5" over stock is about the most mysterious actual measurement I have ever seen.
Example: Frankenlift. It is called a 2.5" lift. That's pretty close to what it measures. If you get a little less or a little more, that would depend on where your stock KJ sat stock. From the factory, there are about 15 different factory front KJ springs to choose from. They are all ordered by VIN. Confusing to say the least. All J has a pretty good handle on which springs will stiffen up the KJ and which ones are too soft. But in the long run, if you are going to lift the KJ compare yours to another stock KJ to see where you sit. If your KJ is up where it should be, than a spacer lift will work for you. A cheaper way to go. If your KJ is a low rider from saggy springs, and sits way low, or bottoms out a lot stock, then don't do a spacer lift, go for the full spring lift. "
