Re: another manifold & riser??
Shaun, It is difficult to answer your question. Lost foam allows for more complex castings in aluminum, than sand casting. However lost foam casting has limitations on the type of metal being cast, due to molten metal temperature. Recently, I believe they developed a lost foam casting method for some types of cast iron.
The bottom line is that if the design of the part being cast is superior in terms of corrosion resistance and long life, it may well have these characteristics, regardless of casting method.