Air shocks?

When I put my 55 Ford sedan together I had the leaf springs re arched, new shocks etc.The car sat too low in the back.I put overload springs on the shocks and put 3\4" spacers between the rear shock mounts and the bottom of the rear shock.At this point the car sits pretty well level.I would like to raise the rear of the car about 1-2" more.I do not want to flip the spring shackles.Any suggestions.