OK , now you have me totally freaked out. My Av is clearly a Z71, but I have the identical RPO codes, front and back in mine, as you noted. Base level suspension. I do have skid plates, and a really cool Z71 logo sticker
Seriously, in all the other threads I have been assuming that I have (or did have) the Z71 rear springs. Well, no wonder my old rear springs were so bad. They sure looked original, and given mine came with a tow brake controller, I am assuming some previous owner was towing something reasonably heavy. And it might explain why I roached the Rancho 9000 shocks so quickly. I bought the front as a kit, that had the 2" saddle extension for the lower shock mount. When I installed them, I should have looked more closely at how compressed the shocks looked when the truck was sitting on the ground.
Do you know whether the heavier torsion bars you noted are a drop in replacement? I think I remember in some thread on some board that 2500 torsion bars are longer than 1500's. And as you have done the homework on this, it would seem in my little pea brain that the heavier rated torsion bar would not change the geometry (read lift) of the front suspension, as the torsion bar is installed with no load. The load coming from the key adjustment? Yes, 340 is really steep, but I have the front receiver mount installed, and on occasion will run my motorcycle in the front, on a carrier. I plan on keeping my Av for a long time. Since i can't go out and spend silly money on bumpers, brush guards and winches and ...., like back in my Jeep days, I don't mind planning for sensible expenses.
Craig
Edit: I just looked up the 6gk bar on GM Parts direct, and they show 209.58. But, the description reads for 3/4 ton models, which as I mentioned above, I think are longer. Really confused.