Well I don't know the exact outer physical dimensions. The dana 35 has 7 and 9/16 ring gear on it, and the dana 60 has 9 and 3/4 ring gear to it. SO the housing is at least 2 inches bigger than the dana 35 to fit the extra gear size. But since it is a heavier duty axle assembly, there is generally more metal to take more of the force. If I remember correctly you lose about 5" of ground clearance over the dana 35.

Maybe SD can get us a picture of a 35 sitting next to a 60?