I could be way wrong on this, but manifold technology has progressed so far from the days these were popular that it might be a backward step for you. If you are building a race engine you probably want it to perform to the max possible, so I would think one of todays manifolds would be a better choice.

If you were building a period piece, like an old time gasser, that manifold would be super cool, but on a race only motor it might not give the results you are looking for,

JMO,

Don