melling soaked n oil for a week. put them in car .sat overnight .went out this morning to put rest of motor back together. and 9 out of 16 were collapsed!? wtf?

 

Soaking in oil wont fill the cavity under the lifter internal piston - it has to be pumped in. What do mean collapsed? How did u test this? U mean u cant move the cup down or its bottomed out? Only on some and not others? '91 formula means roller lifters so u can check them buy hand upside down pushing down on them onto a p-rod and that into a block of wood. Well new lifters the spring that keeps the cup up is pretty stout and can be tough to compress w/o oil inside. My used 125k mi roller lifters with oil still in them wont compress at all by hand.

Sounds more like u cant identify zero lash and have collapsed the cup all the way while adj the preload.

 

they collapse when there isn't any oil pressure and they are holding a valve open, which is what about half of them will be doing at any given time..

 

I had them at zero lash. they were fine when I put them in motor then when I went out to put rest of motor back together 9 of them let go because the rocker arms just slopped around.

 

That makes even less sense than your first post. Im out'a here!