There are a few places that have this info. In my experience, there have been a few that had some incorrect information for some locos, so just be mindful of that. Like any good research project, try to get multiple references for any given bit of info.
For example, info about the F40PH used to be particularly flawed and created a bunch of bad assumptions about donor locos for mechanisms. It is possible that this info has been corrected by now, of course.