They all have oil pumps. They just weren't all high pressure. As for the oil leak, it could be from a number of places. Without being there the only advise is to investigate it & see where it's leaking. You might try putting a piece of cardboard under the truck to isolate the leak from what's already on the floor. You should be able to tell if it's oil, brake fluid or water and also the general area it's coming from. It will cost you in the neighborhood of $2500 +/- to rebuild the engine. If you change the engine out be sure to check your title to see if the engine number is your VIN first. If it is and you replace the engine you won't have your VIN anywhere on the truck. You'll either have to go through the hassle of retitling it with a new number yourself or pass the headache on to the next owner.

Save a life, adopt a senior shelter pet.
The three main causes of blindness: Cataracts, Politics, Religion.
Name your dog Naked so you can walk Naked in the park.