Here is what my Scamp's owner's manual stated, "40 inches to top of the ball. If the sides of the truck are higher than 48" a raised
axle may be necessary." What is really important here is the clearance between the top of the truck's sides (and tailgate) & the bottom of the Scamp's loft. If you know the height difference between the top of the Scamp coupler & the bottom of the loft you would know the clearance Scamp was recommending.
In theory if your Scamp is raised 4.5" lift you could add 4.5" to the ball height and the sides of the truck Scamp recommended above. It sounds like the sides of your truck are 60" tall from the ground.
I would suggest that you set your Scamp on flat, level ground and then level the Scamp with the front legs to determine the dimensions below:
1) What is the distance from the bottom edges of your loft to the ground?
2) What is the distance from the top of the Scamp coupler to the bottom edges of the loft?
3) What is the distance from the ground to the top of the Scamp coupler?
4) With your truck on level ground you could also measure from the ground to the top of the ball on your hitch.
5) From the ground to the highest point of the sides of your truck.
Once you know these dimensions you can figure out the clearance that Scamp recommends between the bottom of the loft and the truck. You can then compare this to the clearance you would have. Good luck, Bert