* 5.9L Magnum V8: A gasoline engine.
* 5.7L Hemi V8: A gasoline engine, a more powerful option than the Magnum.
* 8.0L V10: A gasoline engine, the largest and most powerful option available.
* 5.9L Cummins Turbo Diesel I6: A very popular and powerful diesel option.
It's important to check the specific vehicle's documentation (like the window sticker or owner's manual) to know for certain which engine is installed in a particular 2003 Dodge Ram 2500.