I have a swb econoline its a straight 6 and the van wont move the driveshaft will move but it will not run I took the diff and axles out and didn't seem pretty good my question is whay kind of differential can I use or were can I get it I know is not center it's more to the right and thats weird please help me out thanks in advance

 

The entire drive line is offset, this was done to give the driver room, the rear axle must remain this way, I would say what you have is either a frozen parking brake, or stick wheel all together. Try to remove the wheels and drums, back off the spur wheel on the drums if they won't pull off, be certain the parking brake cable is released too, I highly doubt the carrier or gears are frozen. The rear end is a 9" so any 28 spline center chunk would go right in if you needed to replace it, which is what you'll find in most Ford cars, but you will not be able to just swap out the unit as a whole unless it's from another 69-74 van.

 

I already have it open and I see a lot of metal shavings im try to upload some pics so you can see it and were can I find the axles? ? And the gears

 

Those vans are getting hard to find for parts in junkyards, I say pull the shafts and get them looked at then the center, you should be able to replace the center rather easily, there are many around, the housing is gonna be hard to find, so reusing it is a must.