Anyone ever pop a push rod off the lifter.   I had one pop off to the side after break-in on a high rev run test.  just slid down the tube bi-passing the lifter  Pulled the push rod out, seemed straight.   pulled the dipstick tube, checked with a magnet rod no metal. in the sump no metal junk.    W/O push rod the engine runs. Test:   Pushing the magnet  down into the lifter galley it  raises and down when the engine is turned.   
Guess I will try to instal the push rod to see if I can get the rocker to activate

Any advice appreciated

What valve lash are you running?  Is this a fresh build?  
When you get it back in there and adjusted, observe it with the engine running.  They are supposed to rotate (along with the lifter, as long as said lifter is not hanging in its bore).

Was this after sitting through the winter months? Also check the pocket in the rocker arm to cracks or wear.

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

The other thing that can cause this is a valve sricking open. Tight valve guides, bent valve stems etc. Was this on an exhaust valve?

Had this happen to me many years ago.  Drag race with Dad's 56 Fairlane 292 3 speed.  Was way ahead of other guy so just left it in low for the 1/4 mile.  Not sure of RPMs but was reading about 65 MPH when started running rough.  Dropped 3 push rods.  Fished them back out of block, checked for straight with my uncle (Ford mechanic).  Re-installed and adj lash, all good.  Caused by valve float, miss adjusted valve lash, and stupidity.

Ben HessTulsa,OK

Ben,
You nailed it.  This engine has about an hour of use break in, street, and test.  I ran it yesterday in prep for a drive.  I wailed on the throttle to kick in the secondaries   I wanted to hear all four barrels of the 600 cfm Holly Double Pumper.  Thats when the push rod poped off the rocker and I shut it down.   So thats what Valve Float can do...

Seems no harm done, push rod back in place, revolves with the lifter, all seems good.  Run tomorrow.