I don't know about the particular valving of that shock... but... it is VERY VERY VERY (did I say VERY?) unlikely that 180% anti-squat will want the rebound on full loose. Especially with that big of a tire.
At 180%+ anti-squat, it's trying to hit the tire VERY hard and separate the body. If you have the shock on full loose, it will slam the tire into the ground and use up all of it's travel very quickly in the run. In extreme cases it will actually hit the tire so hard, the tire will bounce back off the ground and unload the tire (which is what's probably happening here).
If you watch the video, the rear is out of travel before the motor ever even makes it up to the flash RPM, within the first 5 feet of the run or so.
The only other thing that would make it act like this is if the shock didn't have enough travel for the separation that the body is trying to achieve at 180%+ anti-squat.
I'm not sure what you have the compression settings at, but if you're going to run the anti-squat that high, I would run them near full tight on compression, and put them somewhere in the middle on rebound to start with.
Full loose on the fronts is fine for now. If you get in a situation where it starts to pitch rotate, and suddenly spins a few feet out, that is a symptom of the front shocks topping out and unloading the rear tire. I don't think that's what you're dealing with here at all though.
Here is a thread I posted last fall... sort of talks about/shows the tire hit that I'm referring to with the shocks too loose.
Mine is a cal-track car, but not so different then your 4-link with the Anti-Squat up that high.
https://board.moparts.org/ubbthreads/show...amp;Search=trueGood luck!
Scott
