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Defective Quadrajet still useable?

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Old Oct 27, 2015 | 09:03 PM
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Default Defective Quadrajet still useable?

Well I've gone back and forth with using the quadrajet that came with my car and and Edelbrock. I finally decided to go with the quadrajet and started the teardown and rebuild today. The carb is a service replacement for a '72 small block 4-speed. p/n 17054927. Its actually really clean as it had very few miles before sitting for a couple decades.

Unfortunately, when I got it all broke down, I noticed that one of the primary venturi's appears to have been mis-drilled in production causing the side of it to be cut off. I tried to get some pics to show it.











Any thoughts on how this would affect the performance of the carb? Does this mean its just junk?

Any advise would be most appreciated,
Mike
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Old Oct 27, 2015 | 09:14 PM
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It looks like some fool stuck a big screwdriver into it and tore the casting up because of the scarring I see. It may still work okay but never as good as it was supposed to.
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Old Oct 27, 2015 | 09:41 PM
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Originally Posted by toobroketoretire
It looks like some fool stuck a big screwdriver into it and tore the casting up because of the scarring I see. It may still work okay but never as good as it was supposed to.
That will never atomize as well as it should.
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Old Oct 27, 2015 | 10:49 PM
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Seems to me that side will run leaner than the good side. It might also be less responsive to small part throttle inputs. The Venturi pull on that nozzle has been somewhat compromised and will not produce as much pull on the fuel nozzle.
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Old Oct 28, 2015 | 07:39 AM
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Originally Posted by toobroketoretire
It looks like some fool stuck a big screwdriver into it and tore the casting up because of the scarring I see. It may still work okay but never as good as it was supposed to.
Thanks for the replies. I thought the same thing about the BF screwdriver but you can see in the first and second pics where part of the casting on the left of the nozzle did not get removed because the drill was so off center and at an angle. Also from the upper side, like the fourth pic, you can see where the opening is off center.

It sounds like I probably need to look at doing something else? Does anyone know if there are differences in carb bodies or could I find one in the general year range and use all of my parts in it?

Thanks again,
Mike
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Old Oct 28, 2015 | 09:58 AM
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Originally Posted by stmiked
Thanks for the replies. I thought the same thing about the BF screwdriver but you can see in the first and second pics where part of the casting on the left of the nozzle did not get removed because the drill was so off center and at an angle. Also from the upper side, like the fourth pic, you can see where the opening is off center.

It sounds like I probably need to look at doing something else? Does anyone know if there are differences in carb bodies or could I find one in the general year range and use all of my parts in it?

Thanks again,
Mike

Are you sure about that carb number provided in the first post? a 1705 carb should have the 5th number as a 5 to 9. These styles were made from 1975 to 1979. There are apparently exceptions to the numbering system as well. Could be service replacements were numbered differently. See what the Julian date is. 4 digit number near the carb number.
You could get the body of another 1705 carb and use it. Here is how to decode your carb number.
http://www.carburetion.com/quadnumber.htm

From this you can see yours should fall in the 1975 to 1979 range.
Here is another chart off of Cliff Ruggle's site.
http://www.cliffshighperformance.com...carb_ID_2.html
Then read the notes below the chart he goes into more detail.

Here is whole carb appropriate for your year on E-bay
http://www.ebay.com/itm/Rochester-Qu...VWFUx~&vxp=mtr

Good price too. Ends in three hours.

Here is another one very much like your current one.
http://www.ebay.com/itm/Rochester-Qu...FWL7xZ&vxp=mtr

Last edited by REELAV8R; Oct 28, 2015 at 10:19 AM.
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Old Oct 28, 2015 | 11:53 AM
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Originally Posted by REELAV8R
Are you sure about that carb number provided in the first post? a 1705 carb should have the 5th number as a 5 to 9. These styles were made from 1975 to 1979. There are apparently exceptions to the numbering system as well. Could be service replacements were numbered differently. See what the Julian date is. 4 digit number near the carb number.
You could get the body of another 1705 carb and use it. Here is how to decode your carb number.
http://www.carburetion.com/quadnumber.htm

From this you can see yours should fall in the 1975 to 1979 range.
Here is another chart off of Cliff Ruggle's site.
http://www.cliffshighperformance.com...carb_ID_2.html
Then read the notes below the chart he goes into more detail.
One thing I know for sure is that service replacement carbs violate the 170 vs 70 rule on year determination.

I don't think the casting numbers for these are well documented because numbers-matching restorers simply don't care about them.
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