I just changed oil from shell 10w30 to castrol gtx 20w50 and now the car is really quiet. Before it was really noisy. I just reached 300K on my car so I put 20w50. Also I read the service manual and it says 5ltrs with filter and 4.7 liters without filter on a LS1 v8. On my previous oil change the oil guy put 6 liters and it was a mess. My oil sensor blew and started leaking. I had to replace it. See picture for ls1 v8.
Some of the workshops here pop 6 litres in the LS1 to stop oil surge, Holden actually changed the capacity of the oil slightly since the handbooks were printed, when my VX SS LS1 had a rebuild back in 2003 for the piston slap issues, they fitted a revised dipstick and tube that took the capaicity to 5.5 litres. I have a copy of the Holden bulletin from the time. I prefer they use about 5.5 when they service mine. I think it also depends on how long they let the oil drain for before refilling, it does not take much to leave maybe half a litre still in the upper areas of the motor if they don't let it drain long enough.
