Well I'm not talking about the foundation. The current tower at Tybee is about 145 ft tall. The original height was about 100 feet. After the Civil War the top 40 feet of the tower was removed and a 85 foot section with a new lantern to house a second order lens was added to the top of the remaining stump.

As for Boston Harbor the current tower was 75 feet tall when built in 1783, in 1859 the lantern was removed from the tower and a section composed of a watch room and new lantern to house a second order lens was added bringing the tower to it's current 89 feet.