Weight difference between 910 and 913 drivers?

What is the head weight difference between the 910 and 913 drivers? I have tried same shafts in both heads and the 913 feels much lighter than the 910.  Thanks.

The finished head weights of the 910 and 913 are the same, however, there are tolerances in head, shaft, and grips that could lead to the difference that you are feeling.  We would recommend having your pro shop change the weight in the head to see if that leads to a better feel for you.