Does it hurt if you over fill a 3.5 ltr engine by half of quart oil?

It generally does not cause significant harm to overfill an engine by half a quart. Most modern cars have a system to prevent overfilling, such as an overflow tube or a sensor that will alert the driver if the oil level is too high. The half quart of extra oil in a 3.5ltr engine is not enough to cause any immediate damage.