Smaller diesel engine, that would replace a gas inline four?

[HH]

HH, you are talking about the Isuzu Hombre.

I've never seen one with a diesel yet, just gas 2.2s.

EDIT: Called a place in edmonton, they said around $3000 for a used 6.2L, just the complete engine, no trans.

It would be the Isuzu Pup, same diesel engine as the S10. It would have been the previous generation to your truck. $3000 seems real high for a used 6.2, should be able to buy a whole used truck for that price.