Build (2) wheel ramps from stacked 2x8's and drive up on them.
Just make sure the angle of incline is not too steep or the scraping sound will be most unpleasant.
This should provide a considerable amount of additional ground clearance.
Here's a DIY video reference:
https://www.youtube.com/watch?v=rQOIQVffO8o
2-1/2 ton hydraulic jack can do the remainder onto jack stands if needed.
Be sure to chock the front wheels if lifting the back off the ground or it will roll.