If you do not have any problems it should be about two hours in and two hours out. At $100/hr you should have $400, plus or minus $100. That is the real world, what a dealer would charge is a different issue. You will then have 2-3 hours set up time if you are installing a new ring and pinion. You don't want a typical dealer setting up the gears. In addition to the cost of the gears you probably want to change the bearings and seals, another $100. If you are a serious racer you will want to drill the ring gear for 7/16 bolts, then, drill the bolts for wire ties, another $100-$200. You will also need six universal straps and twelve strap bolts, probably another $25-$35, do not reuse the old straps/bolts.
Lastly, if your half shafts are difficult to push in/out, you may want to think about new half shafts. There are another set of two straps and four bolts on the outside of each half shaft.
Bruce H.Enthusiast