I'm planning on doing a shackle flip on the rear of my '99 Superduty, the problem I have is that the upper rivits are spaced 6.5" centre to centre and the lower are 6". Should I slot the holes in the frame and then bolt and weld the rear hangers to the frame? Or should I drill new holes either above or below the original ones?

Thanks
JP:trooper:

Either way. Slot the holes or drill new holes below if you've got room on the framerail, this'll give u a little lift too.

What I'm hoping to do is gain 2-2.5" of lift so that I can remove the lower most leaf and my 1.5" procomp blocks; as well as, the upper overload.

JP