A friend of mine has a stroked 440 with 496 cubes, Edelbrock 84 cc heads and what he calls "The famous '509 cam." He has no computer so he asked me to post the question: What gains in performance do people see when switching from the 1.5 ratio to the 1.6 arms? I asked this question about my own 360 combo in another forum and told him that in my post, some guys said that shims may be required to get the geometry right. Is that also true with the big block engines? Maybe if you could tell me what ET gains you have seen, that would help too. Thanks, Jeff.