OK, 4.8, 5.3, 6.0 all use the same oil pans and have the same capacity, 6 quarts. In 2004 the filter was PF44, that was changed to PF46 in 2005. These filters are interchangable. Starting in 2007, for GMT800 and the new model GMT900 the filter went to PF48. The threads were changed and older filters will not fit. You would have to overfill the generation 3, 4, 5 engines 2 to 3 quarts the way the windage tray is designed to began to hurt any thing. The GM engineers say 6 quarts. Thats what it takes.
Now all dip sticks are not created equal as are dip stick tubes.
Just follow the owners manual and sleep well tonight.