Happened on my standard Edelbrock heads with Erson rockers many years back with a reasonably aggressive Lunati solid flat tappet. I put it down to to over revving (lots of 6000's, quite a few 6500's and the occasional zip to 7000, then the valve springs really gave up & I couldn't hit 6!). I covered everything with a shop towel, left individual tips poking through, dressed them with an angle grinder and ran lash caps. They were fine thereafter for many years until the heads came off for a rebuild. Ran lash caps since as I don't think the tips were hardened very well.

Excellent example of valvetrain control damage.  It's like beating on the valves with sixteen little hammers....

Should not have happened.
Most valves have a welded hard tip - stainless is not easy to harden - and you don't want the entire stem hard.
Ferrea does it on race stuff.
Looking at the side of the tip you should be able to see the change in color where a hard tip is friction welded to the stainless stem.
Rollers do focus all the load on a small line contact area.
I also suspect a material issue, valvetrain instability, or grinding through the tip at setup.

ONE Blue Thunder 427 High Riser head.  Was used as a "port model", with a single hand ported intake port, and a single CNC formed combustion chamber.  Other ports and chambers as provided by BT.  Earlier casting with short OE style exhaust side head bolt bosses. 

I only have this single head. No reason for me to hold on to it, and since castings are IMPOSSIBLE to find, this would be good for someone running a race deal with BT heads to keep as a spare or use to service a broken set .

Has been sitting for a decade or more. 
Dusty with surface fuzz on seats etc.
Never installed on an engine. Open to rational offers.
$1300 or ?

Common failure.
Usually from somebody servicing the engine torquing head bolts without blowing out the coolant & crud in the hole first.
Head studs with a bit of silicone and all good.

I have been using TA-31 for a long time now.
Originally designed for use on 6.5/7.3 diesel oil pans.
Obviously good for oil resistance and temperature range.

Send that picture to Cometic. 
Please.

I spoke with them at PRI about that exact issue - but I did not have an image to forward to them.
Restricting that big coolant hole won't matter - but they NEED to "jellybean" the emboss bead around that hole so that it will seal on various blocks.
I have seen several - including my own - with rust on the deck from coolant migration across the surface.

...and agree with Mr. Lykins on that front galley plug - we need to shorten those all the time.

I have seen water migration across the deck with Cometic gaskets a few times.  The emboss bead around some of the coolant/oil passages does not completely go around the opening in some blocks - leaving a portion of the bead overhanging the opening.  Another thing to check....