are the stock rockers supposed to be loose

[dastang2]

are the stock rockers supposed to be loose when the valves are closed. if so, how loose. i am having a problem with this rebuilt motor. i guess it has been milled and i put the thin and thick shims on to make .090 and it won't crank. not sure if it is too loose or not.

 

[dastang2]

i took the thin shims off and it cranked. but still runs like ass. i have to check the lifter preload to make sure it is withing spec. how is this done