This is my $200 dollar special!  I bought it after it had sat 6 months and the owner claimed that  "The oil light came on and started making noise".  The also claimed that the tranny had been rebuilt 2 wks prior to the engine making noise.  So,  we hauled it with the Heavy Chevy home to the CBT garage.  I suspected a bad oil pump or a bad pickup tube,  or the pickup would be clogged.  NOPE!  Someone along in this car's life put a timing chain in.  If you know these engines (3.8 buick)  you'll know that some of them had a plastic/aluminum timing chain to cut down on noise.  Well,  it went.  The brainiac that replaced it didn't clean the remains from the oil pan.   Well,   long story short,  a small piece or timing gear was jamming the oil pressure reliefe valve wide open!,   A gasket set later + oil change and a new belt,   It ran with good oil pressure and no noises!   :-)   Here's the final product....   (118K miles)