They don't seem to require any other tweaking to make them work with just 1" of offset. I would think if you tried to get more, you'd have to start messing with things, but I've never heard of anyone here that's using that method that needed to do anything.
There is no lower spring pad, so that's not an issue. The only thing I can think of that changes with this is the angle of the u-bolts as they pass through the upper spring plate on top of the pack. It "might" mean you needed to enlarge your u-bolt holes a bit, but I don't remember ever hearing of anyone having to do so.
Lots of members doing that mod though, so I'm sure some will pipe up about there experience with moving the axle back.
By the way... What is making you go through this? Just wanting to get a longer wheelbase? Needing some clearance somewhere? Is this an uncut rear truck, or does it have flares?
If old-school flares, they had a pretty steep drop in the leading edge of the rear fender openings. This often led to the larger tires rubbing on the flare itself, and cutting a nice half-moon notch in them.
One cure is to move the axle back like you're contemplating. The other is to use a more modern flare with the larger opening.
If uncut, then it's either cut or move obviously. I prefer move!
Paul
