The chevy will have shorter runners and the heads will probably flow a bit less than the mopar because of the valve angles but it is going to be just a couple pounds lighter, and I litteraly mean just a couple pounds. A few more cubes for the mopar could mean another 10-15 lbs tq also. The rockers on a mopar are on a shaft and should be more stable because of that but the PR angle will cost a few HP from lost valve lift. Both motors have there pros and cons but I think more pros to the mopar with the rod length and shaft rockers

If you went with better cams the mopar really would shine if you used a true .904 lifter cam. With some high ratio rockers it can really get the valves open fast and high, even faster than a roller in a short duration aplication. My own personal example is the cam I just got for my motor, and it is not the maximum rate of lift lobe but it has only 230@.050 duration but I will have .582 lift, try that in the chevy