Ride hight changes

I have been running into problems with my ride height on an a-body. for example I had my ride height set at 7.25" (from the rocker) and after about 10 laps on the track the front dropped to 6.5". as long as I don't jack the car up the ride height will stay the same. once I jack the car up and lower it back down it will raise back up to around 7.25 and stay there tell the car is back on the track. I can pile every one on my crew on the bumper and bounce the front to get it to drop some but not like it dose on the track. I am trying to figure out a way that to fix this or to predict how much it will change with out track time. I have also noticed it when I make an adjustment, if I put a turn in or out it will not change on scales or ride height tell I hit the track. I have looked for binding or worn suspension parts or any thing else that might hold the front like that and have not found any thing yet. I have tried removing the torsion bars and moving the suspension through the complete range of travel. any ideas?
Author: mniks77