Remember to take into account that the airborne will probably be 4 1/2" taller/deeper than the stock pin box. Consequently your trailer nose will be that much higher if you mount it in the same holes as the stock pin box. That is what I found out on mine when I changed. This height change really affected the ride of the trailer!!
If you have a trailer with the axles "flipped" then you shouldn't have any of this problem. My trailer doesn't have the axles "flipped" and I didn't want to do that to it so I had to figure out something else. This led me to all the measuring.
Luckily after much measuring I was able to drill a new row of holes and mount the airborne 2 1/2" higher. I already had my 5th wheel hitch at it's lowest setting.
For measuring; first measure the distance on the stock pin box to the bottom of the trailer nose (as when it would be hooked up). Then measure your airborne the same way. This will give you your difference between the two.
Now put a straight edge across the top of your truck box rails and measure down to the top of your 5th wheel hitch. The measurement of your pin box on your trailer minus the measurement of the truck rails/5th wheel hitch will give you your difference between the bottom of the trailer nose and the truck bed rails. You usually want about 5 to 6" clearance, which is usually level.
Sorry for the long post, but I hope this helps. You want to make sure your trailer sits level after all the work.
Good luck.
