Calling Lars please
Thread Starter
Burning Brakes
Joined: Aug 2001
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From: Bay City MI.
Calling Lars please
I am looking for info on putting a Q-Jet carb on my 467 motor, could you please advise what one would work best for the street? I want good all around performance for the street, not looking to go to the drag strip. Thank you very much!
Tech Contributor
Joined: Aug 1999
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From: At my Bar drinking and wrenching in Lafayette Colorado
Re: Calling Lars please (467-Ratman)
467 -
Since the Q-Jets all flow the same cfm of about 750 (except the SD POntiac and the some 455 Buicks), they all have the same potential for good performance. Select a model style that has the choke system most compatible for your application: the early models are set up for the divorced choke system, so they must be used with an intake manifold compatible with the dovorced choke coil housing. These eary carbs (1968-1974) are also most easily converted to manual choke if needed.
The later models (1975 and later), utilizing the stove choke (hot air tubes) system can easily be converted to an electric choke system. If you're running a blocked heat riser manifold or cylinder heads without the exhaust crossover provision, these later model carbs are a nice setup.
Either way, the carb can be set up and jetted to provide very nice performance on a street-driven vehicle.
Since the Q-Jets all flow the same cfm of about 750 (except the SD POntiac and the some 455 Buicks), they all have the same potential for good performance. Select a model style that has the choke system most compatible for your application: the early models are set up for the divorced choke system, so they must be used with an intake manifold compatible with the dovorced choke coil housing. These eary carbs (1968-1974) are also most easily converted to manual choke if needed.
The later models (1975 and later), utilizing the stove choke (hot air tubes) system can easily be converted to an electric choke system. If you're running a blocked heat riser manifold or cylinder heads without the exhaust crossover provision, these later model carbs are a nice setup.
Either way, the carb can be set up and jetted to provide very nice performance on a street-driven vehicle.
Thread Starter
Burning Brakes
Joined: Aug 2001
Posts: 1,002
Likes: 0
From: Bay City MI.
Re: Calling Lars please (lars)
Lars. Thank you for the info on Q-Jets, my existing setup is a Holley 780 vac secondary with hot air choke on a GM high rise aluminum intake. The heat rise is not block on the manifold. Do you think there will be an increase in performance with the Q-jet, or would the Holley 850dp be a better choice? I know many of our fellow forum friends have said, bigger is not always better! Appreciate the help!
Tech Contributor
Joined: Aug 1999
Posts: 14,382
Likes: 6,402
From: At my Bar drinking and wrenching in Lafayette Colorado
Re: Calling Lars please (467-Ratman)
Rat -
A healthy 467 can certainly take advantage of an 850DP. GM, as conservative as they are, used the 800 cfm Q-Jets on the 455 Pontiacs (Super Duty) and 455 Buicks (Stage 1), and all the Dyno numbers we've run show the big engines gaining an advantage with the bigger carbs. A Q-Jet should perform on par with the 780 Holley, but you'll probably pick up a little on the top end with the 850DP.
For a street car, the 850 may be a bit balky, and will require some stiff gears and proper driving to push it into the secondaries with a smooth transition. The Q-Jet will be much more forgiving, and will allow you to romp on it at will.
I run a 463 Pontiac with the 800 cfm Q-Jet on it. It runs 12.6 on slicks at sea level, so there's no question that the Q-Jet will run...
[Modified by lars, 10:20 PM 8/11/2002]
A healthy 467 can certainly take advantage of an 850DP. GM, as conservative as they are, used the 800 cfm Q-Jets on the 455 Pontiacs (Super Duty) and 455 Buicks (Stage 1), and all the Dyno numbers we've run show the big engines gaining an advantage with the bigger carbs. A Q-Jet should perform on par with the 780 Holley, but you'll probably pick up a little on the top end with the 850DP.
For a street car, the 850 may be a bit balky, and will require some stiff gears and proper driving to push it into the secondaries with a smooth transition. The Q-Jet will be much more forgiving, and will allow you to romp on it at will.
I run a 463 Pontiac with the 800 cfm Q-Jet on it. It runs 12.6 on slicks at sea level, so there's no question that the Q-Jet will run...
[Modified by lars, 10:20 PM 8/11/2002]
