An 8 foot High lift jack? Probably the shocks are gonna bottom out.
Not that dumb of a question. I trimmed my high lift jack a bit, so it would fit cross ways under the back seat. The first time I tried to use it on the bumper, to lift a tire out of a hole, I ran out of jack. Thats when some rocks come in handy, to pile under the jack base.
I've since picked up a small 2 ton floor jack, lifting under the axle, is often easier.
I've used a strap to tie up the axle, but it's often hard to find a good spot to tie to.