There were two engines made for these trucks. The weaker one was a 2.2L I4. The larger and more powerful engine was a 4.3L V6. Obviously, there was quite a difference in performance depending on the engine, as the stronger one had nearly twice the displacement as the smaller engine.
5 speed manual and 4 speed automatic were the only transmission options on these trucks.
There were very few options packages for these trucks, as very few of them were sold in the Isuzu form. The only major changes between this truck and the General Motors versions was the wheels and the front sheet metal.
To say these trucks sold poorly would be a gross understatement. They sold so poorly that they are actually quite rare these days. You can find them popping up on the used truck market, and they don't demand a premium despite their rarity. In good condition they might some day become a collectible. Try looking on eBay for some good deals.