That is kinda frisky for a street oriented cam. 
More street racer than street driver.
Used similar cams often for that purpose. 
I would agree with Brent on the spring deal. 
I used a Manley Nextec oval track spring on stuff like that when I was running traditional four stud rocker mounting - had around 220-230 seat and still only around 600 open.
Couple with a TI or tool steel retainer, set up installed as tight to .050 from bind as you could comfortably get -  and they would do really well.
And I would look at that .012 as a cold lash target - should get you right around .020-.021 hot.
Sometimes hard to define "hot" and keep it consistent through the lash process.  But room temperature cold is easy.

FWIW - and since we are sharing opinions - I have never bought into the lack of oiling as a reason for roller lifter failure - or the EDM hole in solid flat tappets for that point either.

If you ever run an engine at anything beyond idle with an opening in the intake (like the one in the rear of many FE intakes) you'll quickly discover that there is a literal maelstrom of oil flying off on the crankshaft.  I've had oil hit the ceiling of my dyno room.  Watch a crank spinning on a balancer at 750 RPM and it' apparent that this stuff is moving really, really fast.  The open bottom cam tunnel in an FE means that a huge percentage of oil being flung off that rotating assembly is being directed right at the cam/lifter interface.  OEM Ford stuff lasted forever with no direct oiling at all.  The EDM hole in lifters was a strategy employed by NASCAR teams when they were rules mandated to flat tappets, and were using enclosed cam tunnels and vacuum to limit oil movement throughout the engine.  Along with welded stellite faced cams and DLC coated steel lifters.  This stuff simply does not apply to a normal street oriented package.  Oil volume is not the problem.  Sure feels good though... 'cuz we can see it and buy stuff that looks like an intuitive "fix"...

Solid roller lifters live forever in many heavy duty diesel applications, which run at low RPM and light valve spring pressures.I believe the reason they work so well there is more related to valvetrain control than anything else.  Consider the most roller bearing applications - that also last a very long time - run at zero clearance or even in preloaded conditions.  Examples include rear end parts, wheel bearings, internal transmission bearings and rocker fulcrums.  Each roller concentrates load on a line contact and thus transmits every "hit" onto a very small area of the race.  Hit a pothole and the wheel bearing will brinnell the race and the assembly will fail prematurely.  But under normal conditions that wheel bearing will carry 1/4 the weight of a 10,000 pound (or more) truck for decades.  Rollers are not the problem.  Sends us back to the impact/lash and valvetrain control direction. Hydraulic rollers last forever because there in no lash - no impact damage - until the valvetrain loses it's proverbial shit at high RPM.

Unfortunately for us normal folks, valvetrain control is not a simple thing to quantify - other than looking at worn and broken parts and knowing that something ain't right.  Things can be perfectly fine at 7000 RPM and be completely lost at 3000 RPM.  Every darn part in the valvetrain is a spring - the pushrods, rockers, even the cam itself.  If there frequencies all happen to line up the result can cause things to go crazy even at low RPM.  By making these parts stiffer we can get most of the system "out of the way" and focus on controlling things with the spring itself.  Thats the reason for big diameter cam cores, thicker and stiffer pushrods, and steel rockers.  OEM and professional race teams can use computers, labs, and Spintron testing to sort this out, and some serious race engines run with amazingly low spring pressures.  We don't have the luxury.

That is a long way of saying that I really like hydraulic rollers. 
I have run custom made ones with only .015" travel and treated them as solids with the lash "in the oil" at 7000 RPM+.
Set them almost bottomed out cold and let them grow when hot but remain in the travel range - no lash.
Probably not real easy for a guy in his garage on a Friday night...
Get them a teensy bit too tight and the damn engine won't start (experience).
And bushings remove all the roller issues if you can afford to make that step.

Small flashlight(s) with flexible stalks are a necessity.

You can usually bring the roller pair up using some welding wire with a "hook" bent into the end to snag the tie bar.

Once out of the bore, use a couple magnets to walk the pair forward to the distributor hole.

If it crushed out the needles, the debris you're seeing could be the sides of the lifter body alongside the axle.

If that's the case, the lifter will be nearly impossible to remove as the sides spread - and the cam will be toast.

Let's hope that is not the case....

Heck - you might get an extra 10HP from cylinder wall rigidity

We are going to drop the (248) 366-3309 "land line" number to the shop.  With fewer folks in the shop and only one guy to answer the phone it no longer makes sense to have two numbers.  The (248) 931-0358 number is a cell and will remain as the best way to reach me by call or text.

Edelbrock is available - modest upgrade over a factory CJ or MR head, significant upgrade over other OEM iron heads.
I am out of castings
TFS is out of castings
BBM said they had some coming - might already be available.
Shelby might have something - honestly don't know - they are generally pretty proud of their stuff
Pond may have availablility
Chinese stuff is available - Speedmaster, Promaxx, Jegs, ebay - all of it is Steven's heads castings. 

Given the cheaper is better psychology of the market, five years from now the Chinese stuff is all that will be left.

we the people got screwed when the "MAP" policies went into effect.  Courts ruled it was not price fixing, but tomato, tomoto?

I would like to find suppliers other than Summitt and Jegs.

MAP pricing is driven by the manufacturers - not by retailers such as Summit or Jegs.
When I was at F-M and previously at Holley it was a constant battle to get the retail giants to alter their pricing on high volume parts.
Their respective business model was to always be cheaper than everyone else (including each other).
They would sell the higher volume parts below cost if necessary, and neither one would "blink" in a price battle.
All of their profit margin came from deal structure below the invoice - such as volume rebates from the various manufacturers.

This drove all of the little guys in the market out of business, and prevented innovation since cost was the only factor in selling to them.
We as manufacturers would sometimes change a part number just to work around the road blocks this put up.

MAP pricing - as distasteful as it is - fixed this problem.

I've had decent luck with the Heli-coils.  I've had time-serts break off at the "hat" - so I do not use them.