8 3/4 Sure Grip ratio change

OK so it is time to refine my question. I am taking the car to the speed shop in a week or two. Gonna get a variable flow PCV installed to take care of the small rear main seal leak while the engine is running. I'd like to have the shift points sorted at that time as well.

As I mentioned earlier the 727 shifts around 3400 rpm under light to mid throttle. Under heavy throttle the shift points are higher but the tires are spinning. Lots of fun but not ideal for driving. I have the dyno report max torque 533 @ 4000 max hp 471 @ 5200. What shift point should I be targeting?

Sorry but this issue is well beyond my working knowledge. We've had a ton of fun with the car just the way it is. However if it would rev higher at partial throttle before shifting it would be even more fun.

Thanks for the help!!!

PS thanks to the help on this thread I now know the issue is not the rear end gearing but sorting out the shift points.