Well I tried it out and it was not successful. I have purchased a new set of conventional big block springs & shocks. I will be switching back as soon as the springs come in from Moog. I figured I would share my experience with this product in case anyone searches it in the future.
There were no installation instructions provided and the tech line was not helpful. There are two faults with this product that I observed:
1. The threaded sleeve that allows for the height adjustment is not fixed to the shock and does not have any sort of hex nut or flat spot that would allow you to grip it to prevent it from spinning with the adjustment nut once there is pressure on the spring. I made due with a big set of channel locks but it chewed up the aluminum sleeve. Also the shock body it self will spin in place around the bottom mount and the shock shaft.
2. This is a two part second problem. First off the shocks are longer than stock by more than one inch. Secondly the steel adapter plate on the bottom (to spread out the load) will raise or lower the mounting point of the shocks by and inch up or down. I originally though that it was to mount facing downward (to compensate for the longer shock) but the tech line said that they were to face up. I installed the them facing up and was able to get the adjuster to just about 1/3rd up from the bottom before there was too much pressure from the spring to go any higher. The front end was still about an inch lower than it was with the factory springs that I removed but it seemed alright.
When I installed the kit for the first time I still had the small block in the car. It worked ok at first because the springs were the big block set. As it turns out though I only had around a 1/4" of travel before the shocks would bottom out. After I installed the big block the extra weight bottomed out the shock and I had no front suspension (I let some air out of the tire and the rear shocks to limp it around).
I decided to try and flip the adapter plates to give me more shock travel. This seemed to work at first, I raised the ride height adjuster nut to a little over 3/4s of the way up and the shock had lots of up and down travel. However once I put the car on the ground the springs compressed down and the lower control arm bump stops hit the frame and that's how it has been since (parked over winter).
Now that's a muscle car rake. No front suspension and the headers are only an inch from the ground but that's as low as it gets.
Side note: all adjustments to the ride height adjuster had to be made with the lower control arm free of the spindle and sway bar. There was far to much pressure from the spring even at the lowest height to turn the adjuster nut without spinning the shock/sleeve. I did buy the proper adjustment key from pro shocks ($10), it is a cheap pos but it does work.
I do not have any experience with earlier A-Body vehicles. I do not know if the shocks were the same length for the late 60's models. This kit was for big block A-Body's from 68-77.
I finally got the new coil springs in from Moog (back ordered). Managed to get them and the new KYB-G shocks installed. The car looks much better now and it is sitting in the right spot (2-3" travel up, 1" down). I didn't remember to take a picture of it now but I did get a comparison of the two. It looks like I did end up bending the shock when I had it installed with the plate up.
Direct replacement left, pro-shock right.
Using the coil spring compressor for the install is still pretty nerve racking.