need help w/Edelbrock carb

[67Fleet]

I've got an Edelbrock Performer 1805 carb. Right now my truck seems to be running lean as it is detonating at WOT. I guess it could be that the timing is too far advanced also maybe. But for now I'd like to focus on the carb. I don't have the owner's manual for it and couldn't find any on Edelbrocks website. There are 2 screws on the front of the carb, I'm assuming idle adjustment would be one, what is the other? Also, how hard is it to tune one of these? I've never had to mess w/ a carb before. I talked to a master mechanic today who specializes in muscle cars and he told me to junk it and buy a Holley. I don't want to throw away a perfectly good carb just because nimrod doesn't like working on Edelbrocks. I need to try and work with what I have. Any info is greatly appreciated.
*edit: Forgot to mention I am getting extremely poor fuel economy right now as well. ???