Hi: my last two 82 and 83 engines with hydraulic lifters have intermittently had a cold start lifter problem ,even in summer with 5/30 oil.After the first block or so I have to momentarily shut it down and restart to stop the lifters from clicking and then everything is fine.I know it is kind of unusal to feed hydraulic liftes from the top down through the push rod as opposed to oil gallery feed like most engines.I have always used a good brand of lifter on my overhauls like federal mogul and this is not a major problem.Just slightly annoying and confusing for the wife.These engines both carry 45 psig oil pressure on a calibrated guage.Any hints would be appreciated I guess I could always convert to solids with an older cam and rocker arms which I had on all my other 2 dozen leaning towers of power.
Kev

Just throwing out an idea here...

Have you made sure the rocker arms and pushrods are clean?
Does the rocker shaft get enough oil?

Guess you will get better responses later, but I figure that is where I would look first.

How many miles are on these engines?

I would try running a quart of ATF in your oil for 100 miles and then do a oil change including the filter. f that doesn't work try running some Marvel Mystery Oil.