440 Source Aluminum Big Block Heads

Ahhh, but why did the valve break? I just witnessed an Edelbrock valve break and destroy an engine. The valve was hitting the piston before it broke. Well, all 16 valves were hitting the pistons, one exhaust broke before the other valves. Any evidence other valves are failing? What did you have for piston to valve clearance?

The Stealth retainers and locks are not the most quality pieces. Did you replace them when you installed new springs? Is the valve stem still attached to the spring, retainers and locks so you can inspect it?