Hi i have a 96 5.8 liter F -150, and i was going to take my heads off, and have my local machine shop mill it for me



how much can i mill off my mating surface ( gasker surface) and still run 93 pump gas without detonation, and what should my comression be

 

There is no way you could mill enough off to require 93 octane. Your compression ratio is less than 9:1 right now, which will run fine on 87. You would have to get up to over 10.5 to require 93, and that isn't gonna happen with just milling the heads.

I have seen some of your other posts. My suggestion - before you do ANYTHING to your truck, go get some books on Ford performance and read them. You have A LOT to learn before you start making any changes.

 

First your post about headers, and now this? I think 5.8 is a troll.