The manifold that Charley Yapp produces is aluminum and is a copy of a Cragar manifold that was made back in the day. I have one that I bought direct from Charley. This manifold is also sold by Snyders with linkage for $269.95 and is pictured on page A-134 of the newest Snyders catalog and is called Vortex. The Vortex manifold has model A size runners but is probably the best new dual updraft manifold that is now made. The Piranios dyno tests shows that the Vortex dual updraft manifold with model A Zenith carbs gives a 10 horsepower increase on a stock model A engine. This style manifold with a carb near each intake port gives the best results. Cast iron, like the old original performance manifolds were made of is best because they have the same expansion rate as the engine and the flanges on the manifold where the carbs mount aren't as likely to sag from the weight of the carburetors and heat. Its not likely that new dual updraft cast iron manifolds will ever be reproduced. There was another dual updraft that Charley made in the ninties using the original model A manifold with both carbs side by side using a special throttle shaft that was connected. Because of the design of the original intake manifold, this type setup can't perform as well as the other dual updraft manifolds with larger runners, a flat top and a carb near each intake port. Usually with the original manifold modified with side by side carbs, the back two cylinders will run lean and hotter.
