Lifter stuck?

Thanks for the replies and advice. I do agree it’s nearly impossible to diagnose something by a description of what’s going on without actually being there and having hands on. Just thought I’d reach out and see if anyone had seen this before. And if so what they had found was the cause. Obviously I will be much more careful about checking everything as I put it back together. Would you guys suggest complete disassembly and having this thing hot tanked to clear any metal from the oil passages etc? Thanks
I don't know that hot tanking is necessary, BUT DEFINITELY buy yourself a good set of oil gallery brushes, long and short handled brushes and thoroughly scrub all the internal surfaces, oil galleries, all the bolt holes with hot soapy water until everything is spotless. If you have access to a pressure washer, you could use that, too. Then spray it thoroughly with wd40, and blow it off with compressed air. You can use solvent, cut with some ATF to thoroughly wash every individual part until they are spotless. Don't neglect the oil passages in the crank, and the oil pump, inside of rocker shafts, rocker stand holes, every nook and cranny.
When every part is thoroughly clean, inspect every part. When you are satisfied you can reassemble, using clean oil with zinc, and good assembly lube. Use FSM and whatever other guides you can find to help with reassembly. Make sure cam bearing oil holes line up with oil passages in block. Make sure ALL(there's a bunch of 'em) the oil gallery plugs are in place. Search FSM and FABO threads for their locations. Make sure oil spit holes on connecting rods are facing toward cam. When done, prelube engine, making sure you are getting oil to the rocker shafts and rockers. Use a good oil filter, there are plenty of sources on the Internet comparing them.