They'd know for sure, but generally speaking, and with our WH springs specifically, it doesn't hurt a thing to remove a limited number of leaves to fine-tune your ride height.
Usually the bottom two or three will only net you a drop consistent with the thickness of the leaves themselves. So if you remove the bottom leaf, and it's 1/4" thick, that's about all the drop you get. Removing two would net you 1/2" or so and will not effect the ride or load capability "much" at all.
The biggest drop-for-your-buck usually is the third leaf down. It's the first long leaf that is not one of the "main" leaves that are part of either the eyes or double-wrapped front eye.
Removing that leaf will often net you up to 1.5" or so. It will vary per vehicle, but is in that range. It will also have the biggest effect on ride and load capacity, but should not compromise safety or longevity that much. The good part is that, for the street at least, the ride might even improve a little. You just have to watch out if you're prone to loading up with a weeks worth of camping gear for a three day outing. ;D
Street handling (cornering) could be compromised slightly too, but if you're not slaloming in the thing, and your son uses the common sense that you taught him (that Broncos are not sports cars!) everything should be hunky dory.
Measure twice then. Maybe even have someone jack up the front while you're viewing the truck from the side to see where YOU like the stance, then measure the amount of difference.
And yes, keep the leaves in a dark corner of the garage where they won't be in the way, but will come in handy down the road when you either add some weight to the truck, or they sag naturally over time and use.
Paul
