Yes, as long as the flip doesn't interfere with the car body, since the shackles and brackets are above the frame. Flipping the rear shackles will change the pinion angle some, as well, which may or may not be a problem. You can flip the front brackets as well, if it would help.

I bought a set of 2" lowering blocks with the U-bolts & nuts, and free shipping included for something like $30 off ebay a few months ago. I looked but, no longer have the link. I did a google search, a generic ebay listing showed up, and I scrawled down the list until I found what I was looking for, make sure there isn't one with a better price a little farther down the list. Gene