Since the original data is from an ASE service book they tend to be a bit conservative on the oil capacity to keep some oil-pit jockey from overfilling. I typically use 5 quarts with a filter change using the Mobil-1 M104 filter, but do keep in mind that depending on the filter used your actual amount could vary by 1/2 quart. It's always better to run a little low than a little over on oil!