I think you need to describe your goals before anyone can make meaningful recommendations.
When you say "Windsor" do you just mean a 9.5 deck block? Functionally, the deck height is basic difference in the Cleveland vs. 351 Windsor blocks. There are other differences (oil pan, timing chain, dist, etc, but the deck height is what changes the engine's function (e.g., lets you use a longer stroke.)
What HP and RPM in what use do you want? It all makes a big difference. Do you want looks or performance or both? DO you want a smooth engine or one that sounds and feels like a race car? Will you street drive, get onto a track, or open road race?
Ken
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