Author Topic: Quadrajet tuning specs  (Read 5284 times)


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Quadrajet tuning specs
« on: June 09, 2012, 03:49:10 AM »
hey guys,

I have a 69 SS with 350/300hp automatic.  The entire engine is factory numbers matching except the carburetor.  I have another carb that I am going to rebuild, but unsure of the jets, rods, and hanger to use.  I am getting different and conflicting info all over the internet.  So, my question is...what is the correct jets/rods/hanger setup for my car and what would be considered an improvement as far as tuning for performance.  I am more concerned with performance and response as opposed to mpg.  Here is what the carb currently has.

main jets:  67
main rods:  38B
sec rods:  AN
hanger: H

So, what do you guys recommend?




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Re: Quadrajet tuning specs
« Reply #1 on: June 09, 2012, 02:59:22 PM »
Whats the number of the carb you are rebuilding?  

I always take into account the original factory documentation when finding conflicting or variable real world experience postings on the internet. What works for Joe in frozen Canada might not work of Mike in the desert of Arizona.

Look on-line for a copy of the Delco Carburetor Service Manual - I know there are a few versions out there but look for the oldest dated one so you don't have tones of pages for the electronic versions after 81.  My original paper copy is titled:
Carburetor models 4M, 4MC, 4MV Service Manual and it is numbered in the top right corner as 9D-5 May 1973-supersedes 9D-5 dated Nov 1968.
Here is a link to a PDF copy of this manual:

or look for the smaller sized particular Delco - Rochester service manual for the make and model vehicle that carb came off. is a good at cost - cheap - site if you go that route.

In any event any of these manuals will have the specs for all makes and models they were original equipment on.  

My 69 is currently wearing the service replacement 7029207 MT Q-Jet which is specked for all 1969 L48's including Corvette so I have always suspected that the carb was tuned for the higher end vette and not the lower end Impalas when it became a universal service replacement carb. The part number is the original for the 69 vette. I just found my original Q-Jet and will start rebuilding it this summer.

« Last Edit: June 09, 2012, 04:03:48 PM by 69pace »
1969 Z-11 350/300 with 4 Speed
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Re: Quadrajet tuning specs
« Reply #2 on: June 10, 2012, 12:47:45 AM »
Hi Steve,
   The following pages are out of my Rochester collection. They are from the November 1971 set, pertaining to original equipment 350 Quadrajets. They list the original Carburetor part numbers, with all parts. I also included the adjustment and tune up specs for your info.