Crop all pages, then resize all pages and center objects

[rickwtexas]

I've tried and failed many times to crop a scanned pdf document, and then reset page size (5.5"x8.5) with all page elements (re)centered within page space. I've tried cropping (with and without remove white space), editing via page boxes, crop (down) and crop again (back up in size) - no luck. Any tips?

BTW: its over 140 pages and just over 1.3gb so I'd rather not center each manually if possible. Thanks in advance. 

[rickwtexas]

I should add, that all the pages were scanned to 8.5x11, and when you change the page sizing the images detect the original image size and crop to that.