valve noise-oh not again

[JBPM02A@prodigy.com (MR JOHN A DYER)]

Replaced all lifters with factory series on my 85 4000q. Noise came 
back during first week. Use 10w -30
10,000 miles on this set due to a suggestion from another lister, I 
put in Pennzoil synthetic.  Engine was warm and valves clatterring 
when turned off to drain old oil.  Upon startup I got the usual after 
oil change noise but then to my total suprise, three seconds later no 
valve noise!  Have yet to hear it.
87 5000csq lifters with 150,000 miles put in synthetic- no more noise.
 The noise on this car would go away only after the engine warmed up 
before the synthetic.