Carburetor: "Holley NH" Variants
OK, not exactly after-market, but Robb's information is too interesting not to include here (Adrian Whiteman)
Holley NH
The first NH, part number 6200, was a plain tube or straight through design which offered good air flow. It had a side drain angular float bowl and long arm throttle linkage. The one pictured below has the wrong choke crank. It should have only a single arm. The threads in the post extended all the way to the bottom to allow for the short nut that attached the float bowl. The very early straight through carbs also used a cork float.
About 1919-1920 Holley sold the tooling for the Model G to Ford and not long after Ford approached Holley for a license to build the NH. A deal was struck that gave Ford the right to produce one NH for each one they purchased from Holley.
Ford never did produce the straight through NH but modified the design to produce a swayback venturi which proved more effective with the poor quality gasoline available at the time. Holley quickly followed suit.
The NH 6200 is easily identified by looking through the throat. It is also interesting to note that the 6200 data plate is upside down compared to later versions. The NH 6200 B introduced the swayback venturi. It can be differentiated from the later 6200 C by the angular protrusion on post. The 6200 C was introduced with a center drain so the post was changed to allow fuel drainage. If I have misinterpreted the history here perhaps someone can correct me.
The straight through breathes better at higher rpm so it gives more top end power. The straight through I run idles smoothly but not quite as slowly as the swayback. (Robb Wolff)
Photo by Robb Wolff. From the "Accessory Carburetors Stan Howe; Robb Wolff & ?? Collections" Thread.
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A Whiteman
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Carburetor: "Holley NH" Variants
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