[MoT3rror]

The headers are sent in a function called exec_headers(). This function is called in the global.php.
Line 91 in 3.7 R3
Line 85 in 3.6.8 PL2

I couldn't find any hook that is called after the options are pulled out or before exec_headers is called. So you can either put

PHP Code:

$vbulletin->options['nocacheheaders'] = true; 


Or you can modify the exec_headers function to do it per page.