I recently acquired an Edelbrock FM 255 dual quad manifold with Edelbrock 1404 carbs. As usual, I did not do my homework prior to buying, although I got it fairly cheap. I have since found that the FM255 manifold was designed for small port heads as found on '55-'56 y-blocks. It was replaced by the FM257, designed for use with large port heads as found on '57 and up y-blocks. Will the fm255 work on large port heads?

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