Mike Jerry is correct you should be able to run a business card between the intake and the headers. If you can't you will have a vaccum leak at the underside of the intake. You probably noticed that the Fentons and the Offy intake needed some adjustments just to bolt up. It is best to grind on the intake the headers don't have that much meat on them for extensive grinding. This is not a major job just a little spookey at first. You may have to test fit a few times to get it right.
