Why wont my truck start after changing machanical fuel pump? 1986 small block chevy?

I changed my fuel pump with a new one and now it wont start. i took of the line and its not pumping fuel. I made sure the push rod was all the way up with grease but the gap wont close all the way up against the block. any ideas???|||have you checked the pick up tube coming out of the tank for being plugged up or the fuel filter.And one other thing is the fuel pump rod the same length as the one you have in the engine block to operate the pump.There might be different size rod but the other thing you can do is take some starting fluid and spray down in the carb and get the engine to start up in which while you do this it might get the fuel pump rod to operate the fuel pump to pump fuel.The rod rides on the cam lobe to make it pump the fuel.|||Take the pump back off and push the rod up into the block. Slide the pump back in and tighten the bolts evenly. If the rod stays up the pump will mount up flush with the block.|||the push rod is not all the way n u should b able to make it go up agaist the block b 4 bolting r u may have 2 get a spacer plate|||you may want to pull the pump back off and see if the rod is stuck and not coming down if it is up and not coming down it wont let the pump sit flush with the block and it wont pump fuel|||It sounds like the lever is on the wrong side of the cam. Remount the pump, slipping it in so there is spring resistance as you line up the bolts. You will also want to be sure the float bowl is full of gasoline or it will take an awful lot of cranking to get the pump to prime and the float bowl to fill enough to run the engine. The float bowl is filled through the vent, or better yet, by connecting a hose to the carburetor inlet and putting gas into the hose until it won%26#039;t take any more.|||could be the wrong pump check that its IDENTICAL