Zenith Carb Question

jmeckel

Well-known member
I am looking for some information about Zenith 1 carbs. I know Zenith 2 carbs are single venturi. Were all Zenith 1 carbs dual venturi? If not how do you tell which ones were other than if they have a dual venturi in them?

Thanks for any help
 
The Zenith ! means it was made by the Zenith Corporation. Zenith 2 means it was made by Holley company. Zenith 1 or Zenith 2 has nothing to do with whether it is a single or dual Venturi. Zenith did make a Double Venturi - esentially it is a Venturi inside a Venturi - But it only had Zenith on the side and a "Z" on the upper half - no 1 . Holley also made a double Venturi and it is marked with an "H" on the upper and lower halves. The double Venturi's were made in 1927 and early 1928.
 
The change occured in January 1929; Zenith-1 was assigned to the Zenith Company, Zenith-2 was assigned to the Holley Company; when Ford cam out with their Carburetor in January 1931 Zenith-3 was assigned to the Ford Motor Company.

The very early Zenith was a Double Venturi; the bowl was only marked Zenith and the upper housing had a Z on the back side; on the lower housing there was a boss on the back side with a pin which secured the double venturi; on the next lower housing the boss with retaining pin was moved to the front of the housing but the boss on the back side still appeared in the housing but was not drilled. The throttle and choke levers were forged steel with a unique marking.

The Holley double venturi was produced starting in early December 1927; the boss for the retaining pin was on the back side of the lower housing and the bowl only was marked H at the front of the housing ; the upper housing was marked H on the front of upper housing opposite the throat; original Holley carburetors shows the throttle and choke levers were nickle plated.

There is a excellent article in one of the latest "Restorer's" which lists all of the various progressive changes to the upper and lower housings.

One item which appears on all early carburetor lower housings is the brass removable needle seat for the GAV.

Ron
 
Both Zenith made and Holly made carbs in 1928 were made with doubel venturi. Check the Cab book, Zenith Model "A" Carburetor Restoration Guidelines by Steve Paergeter.
 
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