Honestly..... why so shouty... :) its a relevenat suggestion and so i yours probably....
effective makes it way more complicated, how is a man to know what the difference is between actual and atmospheric pressure at the inlet valve at a specific rpm. Or for that matter the resiatance seen at the exhaust valve.. you can work it out for pumps, its easier to fit something in the pump to measure the pressure variation inside and what you see in the inlet and outlet
on an engine aren't you getting into OEM engine design workshop type equipment and analysis with this argument... expensive probes stuck everywhere....
don't dispute its relevance but its a bit beyond building a motor on a stand in the garage
a motor with 10.5:1 static CR will allways have 10.5:1 static CR with a camshaft that is perfect for the job, or one that is totally innapropriate
perfect cam for the job will be ballpark 8-9 DCR
inappropriate will be 5:1 or 12:1 DCR outside the realms of sanity and the motor will be a slug or a hand grenade
There is a place for DCR, as stated its a tool...
stock exhaust and 318 heads on a 273 doesn't indciate an urge or necessity to find out about Effective CR. The man wants a cam that makes his motor a bit better... he's not designing a turbo injected 1 litre for a PHEV
Dave
