I've never "built up" a 400. I've repaired a few. They are basically a "stroked" Cleveland with a 1" taller deck height. Price Motorsports sells intake manifold adapters that will allow you to adapt 351 Cleveland intake manifolds to the wider cylinder head spacing. Heads, cams, intakes, ignitions are readily available. The exhaust system may pose an expensive problem (meaning cu$tom header$). Of course, the induction system will sit higher and most likely will be taller than the engine screen.
George
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