It all depends on how you use the truck. The S10 the T5 will be coming from is a 1/4 ton truck. Can you move furniture or construction supplys with an S10? I would say you could.
Tow a small boat? Probably. Tell you what, I use to abuse the hell out of a little S10 shop truck when I was a sheet metal apprentice. Loaded to the hilt with ladders, welders, gang boxes full uf tools, materials. It was rode hard and put away wet. We had that truck for a long time and never had a transmission problem.
I have a '52 3600 that I plan on using for work and if I did put an OD in it, it would probably be an NV4500. But then again I won't be needing to go much faster then 55, so I probably won't do the OD swap. I have a NWC T5 laying around the shop, I might try it at some point just for kicks, to see how it holds up.
You might also consider a 3 speed with the Borg Warner overdrive. They put them in 1/2 ton trucks.
