This is not a cheap swap!!!
1st of all, 4.56's in both a GM and a Dana uses a unique carrier, with a split at 4.11, so if you want 3.73's you must swap out the carrier as well. As mentioned, 3.73,4.11,4.56 are the best ratio's that will match, other than deeper. Gm went the 3.42 route, Dana...