I have a 70 454 Chevelle LS-5 with posi rear-end. When i press the accellerator the car torques/pitches to the left, and when I let off the accellerator, the car "releases" and torques/pitches back to the right. It is as if one set of wheels is turning faster than the other. I am thinking it may be a rear-end issue, but I don't don't know for sure. Anyone ever heard of this or have any ideas? Thanks!