Rear Thanks

I know it's overkill, but I won't break it. If I can find the heavy duty 8.75 rear,same thing. If I can find one reasonable enough. I've got time. Already have Kelsey Hayes 4 piston brakes and work good to me. Hate to loose em. I'd move the springs in 1/2 inch too with offset hangers for more room.
If you don't mind me asking, what'd moser say it'd cost to narrow that 60?