If the engine is in parts, it will be a great time to do a simple rebuild. Remember this engine is close to 20 yrs+. You should at least replace oil pump, water pump all new seals and gaskets and bearing(main, rod and thrust) piston rings, timing belt. Just grab a haynes or chilton manual, it has the complete rebuild step by step. You can judge from there what you want to do. A rebuild sounds intimidating but its actually pretty easy and cheap, if done right, you'll save $100's. If you do decide to rebuild a great source for parts is partsdinosaur.com Very good prices. Plus if you rebuild it, you'll know your truck from the inside out!