I see, your torsion bars are not adjustable. Everything for my Isuzu is exactly the same as what you just said for your suburban, except there is an adjustment nut on the torsion bar keys to allow you to raise, or lower the front end. The issue is that Isuzu has pretty wimpy torsion bars to begin with so the front end has a lot of brake dive and is squishy in general. The remedy is heavy duty aftermarket torsion bars which in my case, unfortunately, are not cheap.