I used an 11in flywheel and disc when I installed the T5 behind my 261. Had to use a 10 1/2 pressure plate as I couldn't find a part number for an 11in. Do you happen to have the part number for the one you used?
The flywheel and pressure plate I used were from a Camaro. I would think that any auto supply shop would sell a clutch kit for the 11 inch setup. I had my pressure plate and disc rebuilt by Brake and Clutch Supply in Waco TX. Ask for Richie. Great guys and they can build you anything you need.