boing!
give us some more info, does it bounce when you push down on the body? or while riding down the road? when accellerating/decelerating,. is it the famous mono leaf or more than one leaf per side.?
springs are a coil/recoil devise their made to bounce it is the shocks job to stop the bounce, de-arching them shouldnt have effected the bounce just the ride height. if the rear just keeps bouncing when you push down on the bumper a couple times i'd start with a good gas shock... assuming the rear end geometry is set up correctly and its not an acceleration/decelleration driveline vibration issue..
dp1