Oil capacity of 402ci BB

[Jonlopes]

What is the capacity of the 402 Big block when I change both the oil and filter. I tried a search and found answers saying either 5 or 6 quarts.

I believe the oil pan and other parts are stock.

I am going to do a motor flush and change out the oil in my truck to try and help a slightly noisy lifter. The motor was rebuilt in 1992 and only averaged 1500 miles/ year since so I am sure there is plenty of sludge hiding in there.