Thermoquad help

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ChargerST

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First off, let me introduce myself: I'm a 29 yo guy living in beautiful Austria. Heard many great stories about FABO so I decided to join the board. Maybe you guys could already help me out:

I recently got a Holley Street Dominator intake and I decided to rebuild one of my thermoquads I have on the shelf. I have three different models to choose from:

6322S
6545S
9023S

all of them are truck carbs so no emission crap on them. Are they all pretty much identical or is there an advantage of one over the others? according to the Vaanth guide all of them have 4098 primary jets - secondary jets are 5125 (6322S) and 5137 (6545S and 9023S) - should I use the bigger ones? metering rods are 1966 and 2024 - which one is better?

engine is a 440 with headers, 915 heads (compression about 10.5), larger cam, Holley SD intake. automatic car, stock stall speed, 3.23 rear end.

any help is greatly appreciated!
 
Welcome aboard!

Use which ever one has the least throttle shaft play and is in the best overall general shape.
should I use the bigger ones? metering rods are 1966 and 2024 - which one is better?
Click to expand...
This is generally a impossible question to answer since it is a tuning issue you face and you will have to try them out to see how the engine likes each jet and rod combo.
Better off starting with a (Bigger) richer jet setting than a lean one.

Also, the wording, large cam, leaves a lot to be desired. Knowing the specs really helps. Even more so in questions like this.

Give it a go. Worst case... you purchase /change out the plugs.
 
Thanks for your reply. Don't know the specs on the cam unfortunately as the previous owner didn't know either. It sounds like a MP 509 (very rough idle). I read that with large cams I should get a ligher step up spring or toss it completely if necessary.

I'll inspect each carb for throttle shaft play. Don't know how hard it is to rebush the bores if necessary.
 
I can not find replacement step up springs much less performance ones for the TQ. You can use, with effort, AFB/AVS springs. The TQ has a internal cam for enrichment without a spring. This may or may not be suitable.

A decent machinist can bush the shafts easy.
 
The only one that is a truck carb is the 6545. The 6322 is a '73 440 car and the 9023 is a '74 440 car. You may want to measure the diameter of the primary and secondary bores as they made different CFM's
 
Yes, the 6322S was used on more than a few motorhomes in 73. I had a boss who insisted on tuning his and then after he tuned it up he would bring it to me get it to run properly:) The 6322S makes a pretty decent hot rod carb because it has the versatile 1966 rods.
 
The 1966 rods are the preferred rods. They came in all of the aftermarket performance Superquads.
 
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