318>390 Stroker.......Your thoughts

I do not understand why people use DCR...for anything. It assumes in plugging in the cam event that every engine of that size that uses that figure will ingest the same weight of air. Intake design, port flow etc, are going to vary so that a different weight of air will be drawn into the cyl. It is the weight of air that is compressed that will determine the true CR & I do not see how that can be calculated from a static formula that has so many variables.