With a lowered car (tires barely into wheel wells) and a 1 1/4" rear bar, with proper length bolts the rear of the car firms up quite a bit. Disconnecting the bar IMO would allow the rear of the car to squat ALOT more helping aid your wheelspin.
Lol I've actually been thinking about that myself after noticing how firm the rear is after I replaced the bolts to level the swaybar out after lowering. With the 275's I can corner like I'm on rails- which is nice on the street but, wouldn't be beneficial at the track I'm not thinking.
I have a friend with an '86 buick grand national, 455. Hot Rod magazine left a very short note about his car after seeing him at the track explaining that he helped his E.T's by taking out the front shocks, and rolling down the track on just springs. The front tires stay on the ground for the most part while the whole front of the car touched the sky, shifting nearly all the car's weight to the rear. I'm sure disconnecting the front bar would also help in the same manner.