Determine pendulum's maximum angular displacement

Sheneron
[SOLVED] Simple Pendulum

Homework Statement

A simple pendulum with a length of 1.23 m and a mass of 6.64 kg is given an initial speed of 1.96 m/s at its equilibrium position.
(a) Assuming it undergoes simple harmonic motion, determine its period.
(b) Determine its total energy.
(c) Determine its maximum angular displacement. (For large v, and/or small l, the small angle approximation may not be good enough here.)

The Attempt at a Solution

I have solved up to part c), and I can't figure out how to set it up. I thought at first it was
.5mv^2 = mgh and then solving for h, but once I get h I am not sure what to do. Can someone help me get this set up? Thanks.