Lifter Failure after engine run in

[65shatellite]

Hi All.
Looking for a little American knowledge all the way over from here in Australia.

After being in the shop for 2 years, due to some component failure by previous owner, I finally received my 400/500 stroker back from the engine builder with a Comp full hydraulic roller package instead of the previous solid roller build.

We pulled rocker covers off and inspected and noticed one of the lifters was not pumped up even though engine builder had primed it before giving it back to me with 20w 60.
After re installing the engine back into the car, re priming to pump lifter back up and following his run in instructions of 2000rpm for 4 mins, there was a fair bit of valve train noise, we re adjusted lash/preload and motor ran fairly quietly.
We drained oil and cut open filter and there was nothing nasty in there.
The engine had excellent oil pressure the whole time at around 80psi at 2000rpm and 70psi at a 900rpm idle.

The next day, started car up again and was running on 7 cylinders again so I pulled covers again and noticed 2 lifters were now no longer pumped up.

After pulling the intake, rockers, push rods and lifters, it seems that the problem is that the lifters are travelling too high out of the bores at full lift and getting caught. There is light scoring on the bottom 1/4 of most of the lifters consistent with their travel in the bores and some of the rollers now have rough spots when rolling. All lifter bores are fine, non have been re-sleeved.

Is there something that is being missed here? I can't get onto Comp as they are closed but is there a lifter that has more meat further down that comes down over the roller a bit more like a Howard's that will give more support in bore at full lift?

Has anyone else had similar issues?
How can Comp sell this type of lifter if it is such a poor design?
Is there something different about the 400 block lifter bores?
I am now back to the start again minus a big chunk of cash but at least I caught it early this time.

The engine builder doesn't seem to want anything to do with it and has extremely poor social skills which has been a major issue through out the whole build. I was never keen to use Comp components either, so now I am trying to reach out to people that have knowledge of these engines as I am by no means an expert on any of this.

These Mopars are no where near as common as Chev/Ford stuff over here in Australia.

Where do I go from here?

[AKcharger]

I would have thought the roller lifters were "bullet proof"

I saw there was issues with roller bearing in the lifters but that wouldn't cause them coming out of bores...sounds like they might be wrong lifters?

Sorry for the trouble

[b5blue]

Read directions here: https://images.carid.com/comp-cams/items/pdf/camshaft-installation-instructions.pdf?
 Said use 30 or 40 oil and new filter and very specific about valve springs pressure. You said you "adjusted valve train"? Explain what/how?  

[metallicareload99]

What lifters are those? 8921? That wear looks bad from the pictures, but sometimes it's hard to tell. Could the engine builder tell you lifter to bore clearance? I doubt the lifters could get hung up on the edge, at least not without failing catastrophically. I put 1500 miles on this junk and then replaced them with Comp. Note the different rollers: