I suspect the 4 replacements have only been in the engine a short time(maybe a year or so of infrequent driving) being as they looked new and came out easy. I have 4 of the original style ( not from this engine) so I thought it would be better to put them in in place of the replacements. The engine ran fine but had lifter noise even when hot.(lash was adjusted).I believe the older lifters were sticky with varnish. All have been cleaned.
Your thoughts would be appreciated.