bet those 25 yr lifters were stuck,,,were collapsed,,, and pumped up in a combination of all three... so if stuck, some were running solid... some wont pump up... so forth... in your case id think ya want noise untill they break free if they do... try runnin them a little loose and add about a quart of autotransmission fluid to the oil and run it for a while easy, (dont hotrod it) to see if it will clean up and pump up the lifters,,,then try readjusting all of them......the transmission fluid is an old trick for weak lifters....the transmission fuild wont compress as easy as oil...or sumthin like that..... anyway it worked,,,
