Depending on the intake manifold there may be hood clearance, but if you get a low rise dual plane or single plane you should be fine. this site
www.kaufmannproducts.com has info on 351C swaps. I think the 351C engine has the same bellhousing pattern as the windsor engines but i'm not exactly sure. If you do have brake booster interferance you can get one from a later model (87+) because the apparently the brake boosters on those models are smaller in dimension, but i don't think there should be any interferance. I think the primary problems would be with any interferance with specific brand headers because it's a custom installation, but i've heard good things about kaufmann products, they sell at least headers and motor mounts for that swap. Not sure what else though. Good luck, that sounds like a cool swap!
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'84 Mustang 5.0 LX
My car