Rear Jump under hard acceleration?

[mcmmotorsports]

I read somewhere that the rear end of a 4 link can deflect (move) as much as 2".
I have noticed that during hard acceleration that it feels like the rear end jumps a little bit and the car, for a split second, feels like it is going to go sideways.
I thought for a while that it might just be my left hand slightly pulling the wheel on a fast 1-2 or 2-3 shift without even thinking about it.
I am sure that with enough power, a sudden surge of it to the stock LCA bushings might flex, but could it be THAT much to feel like a bad 4 wheel steering setup?
Aftermarket lower and upper control arms are in my near future anyways, but was just curious about this.

 

[codyGT]

I think you might have something wrong. I have only had 2 Mustangs but I have never felt this.

I think is it deflecting 2" there would be problems. Almost every suspension that uses rubber bushings will move a little.

 

[Premium Speed]

my mustang does this at the track with my drag radials on...it feels like it wiggles side to side on the launch and when a slam 2nd...the stock control arms are not very strong as mentioned and i think that is the reason

 

[mcmmotorsports]

We will see if this still exists after the LCA are swapped out.

 

[BullittStangV8]

Im not totally sure if i have the same thing, but sometimes when accelerating and i lose a little traction for a split second after a shift, the rear does "slide" around a little, then hook and hit straight again..ive always assumed that was just a lack of traction causing the slide? Im getting MM LCA and Adj. UCA's put in this week, so that shouldnt be problem anymore..
Mike