I measured about 4-7/8" (+/- 1/16") between the liquid level and the upper flange of a stock 235 oil pan with five quarts of water in the pan, with the pan level. Where the oil pump inlet is will be measured the next time I have an engine in a suitable state of assembly. The GMC inlet screen assembly can drop to about one inch above the bottom of the pan. This would put the screen about 1-1/2 to 2" below the full mark, or about 3 to 4 quarts low with a stock pan. I forget how the chevrolet pump screen would measure.
