Yup, it's true that shocks outboard of the frame rails offer more stability. They work great on leaf springs trucks, but one of the reason's GM engineer's likely never installed shocks this way is lateral movement. When these trucks were new they had skinny tires that were inches from the wheel wells. When a truck is loaded, or just during everyday driving, the rear end is moving side to side as it moves up and down, whereas in a leaf spring truck, it can only move up and down. The reason GM tilted the shocks inside of the frame rails is so the shock essentially moves side to side with the rear axle as it moves up and down. They gave up stability for longevity. If you look at the leaf spring rear trucks of the same years, while they are mounted inboard of the frame, GM put the shocks dang near straight up and perpendicular to the ground because the leaf rears had no lateral movement.
I can see potential wear issues with this kit, and as mentioned above, I could see how the holes on the lower mount could possibly become wallered out from all the lateral movement. But, with all that said, that would likely take a long ass time, especially since *most* of us probably only drive these beasts a few thousand miles a year to dairy queen and back. Again, with
that said, I'd be interested in this kit if I didn't already spend a ton of money on my ECE kit and new shocks...
I wouldn't be able to address my ECE adjustable panhard bar mount with this kit either.
*Just trying to defend my fellow engineers from back in the day
*Assuming the bed still fit (and with mods anything will fit, I've seen floors a few inches from the top of a bed) the shock placement on the green truck above is about perfect. The shocks can move freely "side to side" by going up and down through their cycle, no side to side wear.