How are you determining downtravel? Did you take the measurement from the top of the axle tube to the bottom of the bump stop bracket like I mentioned before?
Yes. I had the frame on jack stands, lifted front axle until it would lift the frame off the stands and take a measurement, then let the axle hang all the way down. I would measure the distance again. The. I subtracted droop from ride height to get just over 3 inches of droop travel.
The drive shaft and shocks were not installed at this point. So there was nothing to restrict the travel.