7.3 New Motor Installed no start

[bigred9909]

so i replaced a 7.3 in a 2000 F250 for a really bad rod knock and today when i got ready to crank it after bleeding the air out of the fuel it turned over but wouldnt start. The glow plug comes on for about 10 sec or so and then goes out so i assume that means the glow plugs r working. what would make it sound like its either out of time slightly or pullin air from somewhere? Any help is greatly appreciated.