Whether on Sites or Funnels, GHL's settings don't actually allow you to install any sort of tracking codes (pxels, etc) into the <head> code of the website, even though it's called "head tracking code". Instead, it always installs into the <body> code.
This is a flawed setting that really should be remedied, as it prevents proper use of tracking and pixels.
In addition to this flawed setting, depending on how your site is built, your head tracking code may be many hundreds (or possibly thousands) of lines of code down before it can even possibly trigger (assuming the code works in the <body>). This means that all of that has to load and fire before you even have a chance of it working, which depending on load speeds would negatively affect this significantly.
Please enable us to actually put tracking HTML into the <head> code, or possibly a way to alter the pages base HTML (maybe with a disclaimer that doing so may break your website, and that GHL isn't liable if that happens).