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glenn in camino · 05-28-2014, 07:18 PM

Can I mix a Holly bottom with a Zenith top? The holly bottom doesn't have a secondary well. Is that normal?

160B · 05-28-2014, 07:34 PM

Quote:

Originally Posted by glenn in camino

Can I mix a Holly bottom with a Zenith top? The holly bottom doesn't have a secondary well. Is that normal?

If there is no brass secondary well that would mean the bottom casting is from a double venturi carburetor, and the cap jet is in a different location. This would not work well with a single venturi. Also there would be a pin boss on the casting to locate the double venturi. Also the idle jet #10 would be used with the integral cast iron secondary well and it is a little longer that a #11 idle jet.

jmeckel · 05-28-2014, 07:37 PM

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If it does not have a secondary well (meaning it is not threaded), if it is threaded it is just missing. The ones without a secondary well need the dual venture and have different configuration of jets. I do not know what would happen if you mixed them up, may not work so well. If you can find the proper top a restored dual venture carb is worth quite a bit more than a single. Some will say they idle better. They do sounds different at idea, the air coming in makes a higher pitched sound.

05-28-2014, 07:37 PM	#3
jmeckel Senior Member Join Date: Sep 2011 Location: Luck WI Posts: 550	Re: Holly/Zenith carburetor Sponsored Links (Register now to hide all advertisements) If it does not have a secondary well (meaning it is not threaded), if it is threaded it is just missing. The ones without a secondary well need the dual venture and have different configuration of jets. I do not know what would happen if you mixed them up, may not work so well. If you can find the proper top a restored dual venture carb is worth quite a bit more than a single. Some will say they idle better. They do sounds different at idea, the air coming in makes a higher pitched sound. __________________ Jon "If you choose to not decide, you still have made a choice!" RUSH Don't tell me what you know..... Tell me what you have done.

05-28-2014, 07:18 PM	#1
glenn in camino Senior Member Join Date: May 2010 Location: Camino, CA. Posts: 3,086	Holly/Zenith carburetor Can I mix a Holly bottom with a Zenith top? The holly bottom doesn't have a secondary well. Is that normal?