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Joined: Sep 2009
Posts: 296
G
'Bolter
'Bolter
G Offline
Joined: Sep 2009
Posts: 296
I will be working on my truck this next week, and have a fresh rebuilt Zenith 228 (model 11963) ready to install. My question is what do I need to look for or adjust on the zenith carburetor once I have it installed. I’m having a little bit of trouble finding how to tune this carburetor for my stock configured 261 engine. I do not have the carburetor with me at the moment, but I am not certain that it has the adjustable jet either. Any guidance?


-Patrick
1953 Chevrolet 3100
261 / 4-speed / 4:11 / Commercial Red

Joined: Jan 2017
Posts: 62
T
'Bolter
'Bolter
T Offline
Joined: Jan 2017
Posts: 62
Also curious as i'm in the process of sorting out carburetion on my 261.

Joined: Nov 2002
Posts: 2,767
C
Carburetion specialist
Carburetion specialist
C Offline
Joined: Nov 2002
Posts: 2,767
The G.M.C. used Zenith type 228 sizes 11 and 12. The 11963 is a size 11. I would have used a size 12 for the 261.

Would suggest waiting until you get the carburetor to see if it has the adjustable main metering jet.

Jon.


Good carburetion is fuelish hot air
The most expensive carburetor is the wrong one you attempt to modify.
If you truly believe "one size fits all," try walking a mile in your spouse's shoes!
The Carburetor Shop
Joined: Sep 2009
Posts: 296
G
'Bolter
'Bolter
G Offline
Joined: Sep 2009
Posts: 296
Is that an easy swap to a 12 if not adjustable?


-Patrick
1953 Chevrolet 3100
261 / 4-speed / 4:11 / Commercial Red

Joined: Nov 2002
Posts: 2,767
C
Carburetion specialist
Carburetion specialist
C Offline
Joined: Nov 2002
Posts: 2,767
Both the size 11 and size 12 have the same 2 15/16 mounting patterns. The differences are internal.

Jon.


Good carburetion is fuelish hot air
The most expensive carburetor is the wrong one you attempt to modify.
If you truly believe "one size fits all," try walking a mile in your spouse's shoes!
The Carburetor Shop

Moderated by  Phak1, Woogeroo 

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