68 gto heater box
 

Anyone know where to get a more in depth drawing on how the 68 gto inside heater box is assembled? I am replacing the heater core in mine and after taking out what seemed like 2 dozens small screws, i was able to get to the core, but while taking the screw i heard something fall inside they are 2 u shaped brackets of some sort, so not sure of function or where to put back