440 is mild

depends on what specs are correct. 440 is fine and perhaps mild for a big block engine. No dispute there.
You should be more concerned with duration, overlap and the the centerline of the cam. You have a large heavy car that needs a broad torque curve. Some cam grind where you are at 500 ft pds of torque at 3000 rpm and holds that torque until 6000 rpm. That is not too tough to do with this engine. Cam spec sheets should give you all the info. TJR