You weblink https://www.pololu.com/product/1390 shows Invenscience i00600 Torxis Servo 1600 oz.in. motor and also there is tab below, in the same page, Selection Options: 3200 ozin. But when I select this option, I still see only 1600 oz.in. Do you have 3200 ozin servo motor of this?
The 3200 oz-in figure used in the drop-down menu is the stall torque for the #1390 Invenscience i00600 Torxis Servo at 12V. The maximum continuous duty torque rating (1600 oz.in) is what appears in the title for the product page, and is shown as the stall torque of the servo at 6V in the “Specs” tab of the servo product page.
If you need 3200 oz-in of torque continuously, you might contact the manufacturer (GearWurx) to see if they have something more powerful.