[Desert Dan]

On my Wrangler I raised the front seats an inch because on the newer Wranglers you sit lower than previous models.

I used small metal blocks cut to the size I wanted as spacers between the floor board and seat mounts. Use longer bolts as needed (grade 8 bolts for safety)
I have seen other people use metal tubing and hocky pucks or roller blade wheels as spacers.

I am sure something like this could be done on an H3?? Make sure you have slack in any of the electrical wires etc.