Oh I get it. Yeah...the pocket between the engine and the frame. Uh...its between the engine and the frame. :wink:
Once you get the axle under the truck...you'll see there is really only one place to put the upper tower, so it makes your choices very easy. It must lean back about 12 degrees or so, and there is not much room on either side of it. There is a clear alley from the tower rearwards, to the crossmember. This is where the upper link must go. It runs at an angle and connects to the inboard face of the drivers-side frame rail. You'll have to re-work the brake lines in this area as well. The link is a tight fit and when you see it in place, you'll realize why nobody does a 4-link on the H3! There just isn't room on the passenger side for another upper link. Before you tack the tower in place...make sure you have your axle exactly where you want it, and also make sure your caster angle (4-6 degrees) and pinion angle (whatever) is set to your liking. Center the tower bracket in the "pocket" and tack it to the tube. Then you can install all three links...install your track bar...cycle the suspension up and down...and make sure the tower stays within the pocket. You should also check the track-bar travel and make sure it doesn't hit the diff cover or oil pan. Bolt the tires on and do some "lock-to-lock" checking during the articulation. Its easier to check all this stuff before you install the coil springs or shocks.
You have longer links than me, and they will connect to the frame further back than mine. Because of this, you may have to put a bend in the upper link. I'm sure it will be very close to the frame rail. Afterwards...you will be able to make slight adjustments to the wheelbase and caster angle but, you'll be limited unless you want to cut this tower loose and re-weld it. I know there seems to be a bunch of emphasis on travel and articulation but, the more travel you want...the more space you're going to need around all this stuff. In all honesty...the SAS-H3 is an absolute beast even with very little travel. My next one will be even lower, stiffer, with less travel, and smaller tires.