Bottom line is if I'm only running a single shock up front, will i need to have it mounted in the factory stock location or can I run the Duff 70/30 in front of the spring? In other words, Has anyone had a problem running a single in this location by itself?
While it's not necessary to run in a specific location, and it can be entirely up to you, the valving needs "might" change with location.
My reasoning is that the location behind the spring has more leverage on the shock than in front. Is it much? Don't know. Never measured it or heard of it being an issue.
The issues that some run into however are clearance with other modifications. Primarily the lower mount is in the way of converting your steering to TRO positioning, and often of things like anti-swaybars and such.
So much so that you hear more often nowadays of people cutting off their lower mounts and going back to behind-the-coil mounting. They might use a hoop, a taller eye-type mount like the "F-250" mounts, or just the stock ones. But behind the spring offers more options.
If I have to buy another pair of shocks for the front, do I get a front shock or a baja bronco rear shock for the front?
Again, might depend on your use. Valving is still critical, and their may be that leverage factor to take into account. But certainly a stock mount will use a shorter shock and possibly be a limiting factor in overall suspension travel. If a custom mount is utilized behind the spring however, then the wheel travel issue does not usually crop up.
The remaining issue can be the quality of the front bracket and/or it's installation. There were many different versions back in the day, and many different positions that it could have been welded on. I've seen some that were poorly positioned and caused a misalignment with the lower mount, and/or interference with the spring tower and larger shock bodies that are more readily available these days.
So you might want to take some additional close measurements of your existing front mounts to make sure the new shocks will fit properly.
Or, if it's not a big deal I suppose you could always extend the upper stud if that was needed.
Personally, I think I'd run the shocks behind the springs. At the very least they seem more protected from rock damage back there.
What I'm looking for in Collapsed length from center to center mounting points is 13" and fully extended needs to be 22-24"
This is both for the front (if you use the front mount) and the rear?
As far as I know they do not make a 7100 that's 13" short. But if you can get away with 14 inches, there are more choices.
They can be had down to 14.21" in the short-body "10 inch travel" version and still get you into the 24" extended length range, or a just slightly shorter version at 14.06" in the "8 inch travel" category if you don't mind being limited to 22.29" extended.
Personally, if that extra 1/8" of compressed length isn't an issue (not sure how it could be at that point!) then the longer extended length can really benefit suspension extension/droop if your rig is set up for it (longer brake hoses and cables and such). If you don't need that extra travel, then it's wide open.
Again, as long as you can live with the extra length when compressed. Do you know your current mount-to-mount measurements at ride height?
Paul