It seemed to me that the lift figure @ .050 was taken at the lifter. If this were the case, rocker ratio would have no effect on duration @ .050. Are the Mopar pieces measured differently?
The rocker ratio would not affect the cam duration at .050,what it would do is hang the valve open a little longer by opening a liitle sooner and closing a little later.The engine would act as if it had about a 2-3 degree larger camshaft,which isnt a drastic change.Also mopars cams are rated like everyone else in the industry,.050 is the standard,the only real difference is when comparing the .050 numbers to the .006 or advertised.You can have two advertised 280 cams and one will be 230 @ .050 and the other one will be rated at 238 @ .050,this indicates a more agressive lobe profile.Mopars are old but they were a pioneer of agressive ramps,their lift numbers were kept low to compensate for stock heads which generally peak in the lower lifts.