Hi Donna-L,
Welcome to the Heartland Owners Forum and Family. We have a great bunch of people here with lots of information and all willing to share their knowledge if needed.
I'm not sure what Heartland unit you have, but if the springs are under the axles, I can see no reason that they could not be changed to give a little more clearance. Just make sure they are mounted correctly in the proper saddles and everything. Just need to be careful of overall height.
Enjoy the forum and your new toy.
Jim M