been researching ford e350 and chevy express 3500 van axles for another swap and have come across some interesting dana 70 and 80 options, I don't remember seeing threads pertaining to van swaps, but am hoping someone might chime in their experience, the 1999 - 2004 productions have our 8x6-1/2" lug patterns, after that its metric, the d70 in the express is a super 70 with nodular cast gusseting running the 35 spline axles at 1.5 thickness, an upgrade from my 32 spline, the axle tubes are 3.5", the spring pads will likely need to be moved. the d80 runs the 4" axle tubes so plates will need to be addressed, some were produced with 37 spline axles, and so far im seeing them at 10 lug, with bigger spindle bearings. the salvager ive been in touch with has a bunch od these axles but wont code the ratios from the scan tags, "bom" numbers, I need to get bom reference to identify ratio, im hoping to find a 4:10 with posi. measuring width, wheel mount surface to "wms" im 64" and the vans are very close, im also seeing on Yukon gear site the d80 was used as far back as 1988, some ran the d60 too. I have the egr conversion on mine, my problem is when changing pads, 1978 Eldorado calipers require pressing and spinning the piston to retract it down, and usually causes a check valve on the face of the piston to start leaking, and prevents me from driving for another day while sourcing it, im all about redundance, and cant fathom a backcountry brake problem, the later axles have drum ebrake, and single piston dependable calipers, just my style, so the search begins. theres also a article I came across in four wheeler magazine archives titled "1990 ford f350 brake upgrade, where they swapped the sterling to the d70 from a 2004 3500 express, for anyone pondering this swap.

 

I have some experience with the E350 dana 60 you mention. it was a year 2000 axle, 8x6.5 pattern, ~65" wms to wms, 35 spline full float, 4.10 open diff (swapped in a Yukon though). I ran this in a CJ5 wheeler for about a year and then sold it to a buddy who is now still running it in a Ranger trail rig on 40" tires. we have both abused the heck out of that diff and the thing just doesn't break! his truck has a 5.0 with probably 300hp/300 ft lbs but it's backed with a t-18 and an atlas 4:1 t-case, crazy low gearing = crazy amounts of torque on that axle with 40" tires! we did weld the tubes to the center section.

as for brakes, all I ever did was put new pads on it when I first built it and that was it! e-brake worked just fine as well. spring pads will need to be moved as you mentioned