hey everyone i have no clue whats wrong with this truck. i just put new heads on a 95 model with the 5.0 liter v8. when i go to starrt the truck as soon as it engages the starter, it kills the battery out. anyone know whats causing this? i have replaced the battery and starter

 

Welcome to the site!
Could you give more detail on 'kills the battery out'?
Was the truck running before the head replacements?

 

You have a loose or dirty battery cable connection or ground cable connection. Possibly a bad, internally shorting, cable. . Most likely you will find the problem with a dirty or loose cable near the battery. Did you clean the inside of the cables good when you installed the new battery?