Author Topic: Carb question  (Read 9187 times)

Offline 1979C20

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Carb question
« on: December 12, 2010, 03:31:14 PM »
Would a Holley 750cfm double pumper part#r84013 be too much for a basically stock 350 with a 440 292 comp cam? Stock heads, stock crank, stock pistons, stock intake, stock distributor, headers, about 2000mi on engine. Daily driven, like its a race car. Haha. I only get about 8 or 9mpg with my stock qjet that needs replaced/rebuilt. So I dont expect much mileage.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline Captkaos

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Re: Carb question
« Reply #1 on: December 12, 2010, 11:04:37 PM »
Yes.

Offline 1979C20

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Re: Carb question
« Reply #2 on: December 13, 2010, 01:00:10 AM »
Really? I searched online and was told the stock rochester q-jet was a 750-800cfm....
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline Irish_Alley

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Re: Carb question
« Reply #3 on: December 13, 2010, 04:14:14 AM »
The quad can be tuned on to run that much. A Holley you want no more than 650 with a stock engine. You will find if you want better gas mpg than your gearing should be lower than it is and drive it like an old man
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When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline Grim 82

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Re: Carb question
« Reply #4 on: December 13, 2010, 09:23:11 AM »
To save money and get better mileage rebuild the q-jet. If you just want a shiny new carb a 600 cfm Edelbrock or Holley would be plenty for a stock 350. You would need the adapter plate to put it on your stock manifold if you buy a square bore carb.
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Offline Captkaos

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Re: Carb question
« Reply #5 on: December 13, 2010, 11:31:05 AM »
Q-jet is MAX Flow of 750-800cfm.  It runs on 2 small primaries for the most part and the secondaries work on Vacuum demand, generically speaking the motor will only pull what it needs.

A double pumper has a mechanical secondary and when it is engaged it will dump the fuel in regardless if it needs it or not.


Offline 1979C20

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Re: Carb question
« Reply #6 on: December 13, 2010, 02:16:23 PM »
How do you bolt the adapter plate on? My dad had on in the shed out back, mr. Gasket square to spread. It has 4 2sided studs, 4 nuts, and 4 washers.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline Irish_Alley

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Re: Carb question
« Reply #7 on: December 13, 2010, 03:13:35 PM »
Bolt it to the intake then bolt the Carb on
If you canít tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline 1979C20

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Re: Carb question
« Reply #8 on: December 13, 2010, 04:05:26 PM »
But how? I dont understand how it would bolt on.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline Grim 82

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Re: Carb question
« Reply #9 on: December 13, 2010, 04:12:52 PM »
There should be recessed holes to bolt it to the intake, then 4 studs that thread into the adapter, then put the carb on the studs and put nuts on them.
Give a man a gun, and he might rob a bank. Give a man a bank, and he might rob the world.

Offline 1979C20

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Re: Carb question
« Reply #10 on: December 13, 2010, 04:19:20 PM »
Anybody have pictures of how to install one? Because there are several holes and what now. Like I said, I have 4 2 sided studs, one side is course thread that I believe threads into the intake manifold, and the other side is fine thread which matches the 4 nuts.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline Grim 82

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Re: Carb question
« Reply #11 on: December 13, 2010, 04:28:37 PM »
And you need 4 bolts to bolt the adapter to the intake. The fine thread end of the studs thread into the adapter. Make sure you use 2 gaskets.
Give a man a gun, and he might rob a bank. Give a man a bank, and he might rob the world.

Offline Grim 82

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Give a man a gun, and he might rob a bank. Give a man a bank, and he might rob the world.

Offline 1979C20

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Re: Carb question
« Reply #13 on: December 13, 2010, 05:22:35 PM »
There are no threaded holes on the adapter plate. how does it bolt to the intake and carb? nuts on either side of the plate?
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline Grim 82

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Re: Carb question
« Reply #14 on: December 13, 2010, 06:03:03 PM »
Lets see a pic of the adapter.
Give a man a gun, and he might rob a bank. Give a man a bank, and he might rob the world.