All of the Pontiac V-8s use the same oil pan. They take 6 quarts with a new filter. You need to run the engine so the oil gets into the filter and all the galleries. Let it drain back and then check the level. You may have the wrong dipstick. Another problem I have seen is that when someone does work on the engine, they forget to put the lower dipstick tube guide back. It bolts to a main bearing cap and guides the stick away from the crank shaft. Without it, the stick hits the crank. Then they use a shorter dipstick, solving that problem, and creating another.