Re: Replacing a 460 Big Block
I'm not sure why everyone is jumping on the "get a used axle from a junkyard and go" bandwagon, because it'll take a lot of effort to go that route for a used axle that may or may not last (who knows if it's in good shape unless you take it to a shop and have it gone through). If it were me, I'd take it to a shop and have the gears replaced in the differential. If the carrier is toast, go to a junkyard and pick up a carrier, and take it to a shop along with the van. Have them clean-up the used carrier, install new gears and bearings, and install in the van. That way no swapping brakes, brakelines, wheels, u-joints, etc. And you'll have a completely rebuilt differential with new gears that will be under warranty and last a long time without all the hassle of dropping the axle and swapping. Plus, it should be well under $2G's.
If you sell the van inoperable you'll take a bath! If you fix and sell then you'll be sending a good van with new motor and gears down the road to be replaced by something that will cost more initially and be an unknown. The only reason I can see to sell the van and replace it with something new is to upgrade to a diesel or an EB. From the pics in your gallery the van looks clean and nice, and you know everything about it. I'd keep it and have the differential rebuilt.