440 head noise. Perpetual problems. Problem solved

You can get that tool Ben posted at sears, and if you used the hammer trick (ouch:D) to get the locks out, how are going to get them back in?
The rope trick was mentioned above but as long as that piston is up all the way the valve can't fall in the cylinder.
If you want to use the rope just get that cylinder coming up on the fire stroke with both valves closed, feed about 24 inches of 1/4 nylon rope into the plug hole and turn the engine till the piston presses up against the rope.
This can be used on reassembly if the valve tries to fall down to low to get the locks back in after the spring is back on.

I used a piece of an old sheet to keep locks from falling down inside the block through the pushrod openings if one slipped or popped out.