Yup. To make matters worse, you need to mill something like .375 off of each flange to fit it in the valley.
Look at the pics George posted of the manifold. Notice the thickness of the flanges? Ain't no way you can mill that much off of them. Your only hope is that the manifold comes close to matching your ports as a stock 9.5.
Good luck, you're going to need it.
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