backfire? help

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i just put an ls in my car and its making this backfire noise when i try to start it and it wont start. any ideas?

i held the key for about 5 seconds and it was trying to turn over, the engine sounded a little less turbulant but still nothing. i pulled the key out went to start it again, when i turned the key to let the fuel pump prime, the fuel pump started making a wierd noise as if it wasnt getting grounded. the lights on my guage cluster also started flickering, along with a slight bouncing of the thermostat needle.
when i turn the key the car dies. i just got the battery recharged yesterday.
the only thing that changed since the video is i switched around the 2 and 4 wires.

any suggestions?

also, i did not install the trans mount that goes on the front of the transmission, could this be causing grounding problems?

http://tinypic.com/player.php?v=vf8b37&s=5
video^