Arcosine, thanks for the link to those GM codes.
Here's the inside of the glovebox on my truck.
One of the codes is GT5, which indicates rear gearing of 4.10. I believe this was the lowest stock gearing available on S-10s. That would make sense, since it's the 2.2l 4-cylinder (less powerful engine) AND extended cab, which makes it heavier.
I believe that the low gearing would be a disadvantage to the diesel engine, but an advantage to the electric motor. Likely, I'd have a relatively low top cruising speed on the diesel. If it were somebody else, that might be a problem, but I don't mind keeping my speed reasonable on the freeway.
I think the 4.10 gearing should be fine.
EDIT: I also looked in the junk truck. That one says GT4 on it, which would be 3.73 gears. That truck really is junk. I only have it as something to test-fit and experiment on. I wouldn't want to use it's whole rear differential, but if I really wanted to, I'm sure I could take it apart and get that gear out.