There is no reason to shift point a SB mopar or any engine to insane RPM's if it stops making power 1000+ rpm lower the shift point. The one reason to spin it higher is if you are running a gear that requires it to spin out the back of the 1/4 mile in high gear.
Some cars/engines like being shifted slighlty above the peak HP observed on a dyno. In the 200-400 rpm range. I've never seen a set up that liked 500 or more rpm.
I used to drive a lot of cars many years ago at test and tunes and street racing. I'd ask most of the owners/drivers where they shifted. Almost every time I would shift the car at a lower RPM and the car would pick up et. DOH!!!! One car I got told it was shifted at 5900. Knowing the set up, shifted at 5400, car picked up .15 ET at the stripe. Go figure. It was a BB mopar :) More RPM without benefit is just unnecessary wear and tear on the mill.