The axles will swap in fine, as long as the u-joints are the same but you have to be careful that the axles your putting in are in decent shape, gear wear, brakes, wheel bearings ect or you'll end up rebuilding them anyway. You will see a noticeable improvement in the get up of your truck with the ratio change, and quite possibly an increase in fuel mileage due to the engine not working as hard to turn the tires. As long as you don't plan on hammering your truck, the 10 bolt rear should hold up fine. Also check the steering linkage for wear and front hubs, ball joints ect.