9/16" x 20 tpi is the thread used for most good quality bike pedals and cranks. The left pedal is left-hand threaded, hence the need for that particular threaded helicoil.

Bike Tools Etc has pedal thread repair kits that include 9/16x20 helicoils, both left and right hand threaded. Look here and scroll down:

http://www.biketoolsetc.com/index.cg...ad%20repair&s=