A I recall, the Fenton flanges/ears are thicker than the Offenhauser ears/flanges. I slowly and carefully ground down the Fenton flanges/ears until they matched those on the Offy intake. Then I used the original bolts and "clamps" (actually I used the original clamps and stainless bolts from Totally Stainless).
The bigger problem I had was taking enough metal off the intake and exhaust manifolds so that they did not touch. Use paper (carbon paper if you can find it) to place between the tight edge to be sure they do not touch when you clamp them together to the head. As I recall, I ground metal from the Offenhauser edge but still had to cut a matching "groove" in the Fentons. They now match up fine.
I used a bolt with washer at each end of the Fenton/head, even though originally a stud was at each end.
Tim
