62 GMC Self Lowering and Raising

[62gmcsbc]

Hello all, my 62 GMC seems to be lowering in the front by itself whenever it feels like it, then it will raise its self mostly after a drive. The lowering seems to be when I dont run it, but no all the time. The difference seems to be about an inch up or down. I have the stock torsion bar suspension with the exception of the McGauphys lowering spindles with disc brake set up. Any ideas why this is happening? Again it doesn't do it all the time but I like the way it sits when it lowers itself and want to keep the stance. Thanks ahead of time.