judging by the @ 050 #'s the 278 is milder.
222@ compared to the 268's 224/230.
OK my question is why does the 268xe give a broader power band according to comp cams 1800-5800 vs cranes 2400-5400? They both run a 110 lobe seperation.

I ran the crane 278 in my 396 and it ran well. but you must remember that that grind is based on 20 year old technology. the comp cams x-treme energy is based on new technology as valve opening and closing and would probably be a better choice. although my carran easy 12's with the crane 278. I used a 11" converter and it pulled 23" of vacuum while idling @ 800 rpm. good luck