It sounds to me like you may have installed the lift pump with the cam lever sat beneath or under the cam shaft as opposed to up and in front of it. Remove the lift pump and with the cam lever pointing away from you, place your thumb over the left hand (OUT) union and manually force the cam lever up and down (not the small hand priming lever but the main arm that rides on the cam). It should force air past your thumb. Move your thumb to the opposite (IN) union and it should create a vacuum. Refit the pump being sure that the cam lever is kept up and infront of the cam as soon as it starts to disappear into the cam gallery. DO NOT try and hook the cam lever down and under the cam - that's not how they work. Bolt it back into position. If the cam lever is resting against the cam lobe you will find that it becomes difficult to tighten up. This is very normal, just ensure that you tighten it down evenly to prevent damage to the bolt threads / pump body. Re-connect your fuel lines (fuel in from the tank to the right, fuel out to the filter head to the left) and then turn the engine over on the key. If it is not pumping fuel, you have a buggered lift pump so take it back and swap it for another. They are terrible things at the moment. I have been through 7 within the last two years, most Delphi units, some other makes, each of which have failed in different ways. I have now gone down the electric fuel pump route.
-Tom