A body BB manifolds on ebay
Power steering likely wont work with the 440 original manifold. A 383 68/69 casting yes power steering and these cars were offered the option in 68/69 with the new drivers side manifold casting 383 only. There was a special power steering hose connection for use on the Big Block A's. The A's had many unique parts to get this B/RB engines in the A's.
As for Schumaker Headers, I have two sets for my cars,,,Tri-Y and one set modified for 4 speed use. Again, if your resorting a car to factory then schumaker headers are not what a guy would want no matter what the power loss. The Tri-Y manifolds are perfect for the street and fit well...save the TTI's for the track if thats what you do. Tri-Y is just an alternative to trying to find cast manifolds for these cars. Tri-Y's give us all an option for street driving and let the engine breath a bit better. For me it is all I need,,,,I dont race it,,,just have some street fun...perfect for my intended use. Thats just me. I need to find the picture of the manifolds all in a row that I have,,,comparison, I did not have the 440 manifold for the picture.