Wind your grandfather clock. This will shift the weights toward the seat board. Be sure to wind the pullets until they're right above the trunk door top.
Remove the hood of the grandfather clock. Use marking tape to secure the gut line around the strike and going barrels to keep the moving parts from shifting during the moving process.
Remove the left and right weights. Mark them with a piece of masking tape and the letters "R" and "L" so you can tell them apart.
Remove the pendulum from the movement, and lift the movement and dial from the grandfather clock's case. You'll be able to lift it all up with the seat board.
Wrap the pendulum, movement and dial in bubble wrap and put them in a moving box. Make sure the movement and dial remain upright. Do not set anything else on top of them in the box and keep that box on top of other boxes.
Cover the grandfather clock with bubble wrap, making sure the bubble wrap is taped to more bubble wrap and not the clock. Lay down the clock in the moving van so it can't tip over during the trip.