Hi
Daully rear ends trac both wider and narrower than the srw diffs.The wide ones are for trucks with pickup boxs,and the narrow ones are for cab and chassis.I happen to have both sitting in my parts pile.You can convert a srw diff to dauls by changing the backing plates and drums fror a daully diff.The daul wheels wouln't go over the srw drums.But if you change a pickup daully rear diff to srw the trac will be way off and will look odd.And if you change a srw to daulls you will have to cut out your wheel wells in a pickup box.I was going to put dauls on a srw diff on one of my trucks.Was going to cut the wheel wells out of the box,then it wouldn't be as wide as the dually trucks are,but i wouldn't be able to haul anything that was 4ft wide between the wheels,eg a camper.I think the look would be nice the duals would stick out a little,a flare would take care of that.
Have fun
Thomas
90 Chev 3500 c/c 4x4,6.2na,400 auto,4:10 gears.DSG Timing gears,main girdle, isspro tach, pyro,boost,oil and trany temp.Dual Tstats, High volume peninsular pump,on shelf, Custom turbo and intercooler 85%complete. Change of plans for the dually, it's going to get a Cummins. Both trucks are Blue 90 4x4 crews