64-66 Barracuda 360 Best Exhaust Manifolds?

That depends on if you have manual or power steering.
If you have manual steering, the early or late 340 manifolds will work, as will the later Magnum manifolds. Both may require a bit of tweeking (shimming the engine mounts, a touch with a grinder) for column/coupler clearance, the Magnums especially.
With factory power steering (I can't speak for the Borgeson box), your only real choice is the factory early A 273 manifolds, which aren't the greatest for a performance build; but they're the only manifolds I'm aware of that will fit and clear everything.