I`ve owned several cars with the 3800. Always super silent! I always ran dino in them,usually Valvoline. I even ran the orange can of doom and never had a hint of an issue with those motors. Here`s a couple of examples:
When I bought my 2nd 3000GT (car had 30k miles on it),it ran super silent and smooooooooth as silk,UNTIL I changed the oil to Syntec 10W30. Immediately it ticked and slapped like crazy on every cold startup or startup after it had sat for a few hours. Ran it like this for a long time,thinking I`d bought a lemon. Well,I changed the oil back to regular dino and all ticking and slapping were immediately gone and never returned.
Same thing with my gf`s Delta 88 w/3800. Ran smoth as glass till I changed the oil to M1 10W30. Then,it ticked on ever startup,hot or cold. Went back to dino next oci and all abnormal noises were gone and never came back. Do some engines simply not react well to synth oils? I`m no professional mechanic so I can`t make a scientific conclusion,but something didn`t mesh well.