Carb
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
If you have a Q-Jet on the engine now, spending money for a "better" carb with more potential for power and better efficiency would be a total waste of your funds. Rebuild the carb or send it to Lars to rebuild it.
There is NO CARB MADE that will outperform the Q-Jet for smooth transitions, power, or efficiency. They may be easier to work on; but once the Q-Jet it tuned properly, you won't have to touch it again.
There is NO CARB MADE that will outperform the Q-Jet for smooth transitions, power, or efficiency. They may be easier to work on; but once the Q-Jet it tuned properly, you won't have to touch it again.
Drifting
Joined: Sep 2010
Posts: 1,412
Likes: 50
From: Laguna Niguel California
If you have a Q-Jet on the engine now, spending money for a "better" carb with more potential for power and better efficiency would be a total waste of your funds. Rebuild the carb or send it to Lars to rebuild it.
There is NO CARB MADE that will outperform the Q-Jet for smooth transitions, power, or efficiency. They may be easier to work on; but once the Q-Jet it tuned properly, you won't have to touch it again.
There is NO CARB MADE that will outperform the Q-Jet for smooth transitions, power, or efficiency. They may be easier to work on; but once the Q-Jet it tuned properly, you won't have to touch it again.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
You don't even have to strip off the emissions stuff. (And you don't want to if your state requires emissions testing of your vintage car.)
But, you DO want to move the vacuum hose for the distributor advance can over to a manifold vacuum source on your Q-Jet (instead of the 'timed' /ported vacuum line as it came from the factory). Doing so will put vacuum advance back on the engine at idle, which will improve idle quality, let engine run cooler, and reduce fuel usage at idle.
But, you DO want to move the vacuum hose for the distributor advance can over to a manifold vacuum source on your Q-Jet (instead of the 'timed' /ported vacuum line as it came from the factory). Doing so will put vacuum advance back on the engine at idle, which will improve idle quality, let engine run cooler, and reduce fuel usage at idle.
Burning Brakes
Joined: Sep 2016
Posts: 955
Likes: 442
From: Dutchess county New York
I looked through replacements and like some of the Holley Quick Fuel Slayer carbs. At least with the rebuild I didn't have to fool with different cables, brackets, etc. Minor.
Last edited by pigfarmer; Apr 14, 2018 at 08:15 AM.
Racer
Joined: Mar 2015
Posts: 492
Likes: 40
From: SE Ohio
St. Jude Donor '16-'17-'18,'19
If you have a Q-Jet on the engine now, spending money for a "better" carb with more potential for power and better efficiency would be a total waste of your funds. Rebuild the carb or send it to Lars to rebuild it.
There is NO CARB MADE that will outperform the Q-Jet for smooth transitions, power, or efficiency. They may be easier to work on; but once the Q-Jet it tuned properly, you won't have to touch it again.
There is NO CARB MADE that will outperform the Q-Jet for smooth transitions, power, or efficiency. They may be easier to work on; but once the Q-Jet it tuned properly, you won't have to touch it again.
Just send to Lars. He did mine and it runs great.
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Verdad Gallardo
Tech Contributor
Joined: Aug 1999
Posts: 14,379
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
Instructor
Joined: Sep 2010
Posts: 111
Likes: 4
From: Grosse Pointe Michigan
You don't even have to strip off the emissions stuff. (And you don't want to if your state requires emissions testing of your vintage car.)
But, you DO want to move the vacuum hose for the distributor advance can over to a manifold vacuum source on your Q-Jet (instead of the 'timed' /ported vacuum line as it came from the factory). Doing so will put vacuum advance back on the engine at idle, which will improve idle quality, let engine run cooler, and reduce fuel usage at idle.
But, you DO want to move the vacuum hose for the distributor advance can over to a manifold vacuum source on your Q-Jet (instead of the 'timed' /ported vacuum line as it came from the factory). Doing so will put vacuum advance back on the engine at idle, which will improve idle quality, let engine run cooler, and reduce fuel usage at idle.
The only ported vacuum port is on lower throttle plate on passenger side of carb but it is modulated meaning the amount of vacuum tapers off as the throttle plates continue to open because it’s used for the EGR valve. I just went through this with Cliff Ruggles.
Tech Contributor
Joined: Aug 1999
Posts: 14,379
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
If the carburetor is the correct qjet for 75 automatic (7045222) the correct vacuum port for distributor is the upper port on driver side of carb and it’s full vacuum at idle.
The only ported vacuum port is on lower throttle plate on passenger side of carb but it is modulated meaning the amount of vacuum tapers off as the throttle plates continue to open because it’s used for the EGR valve. I just went through this with Cliff Ruggles.
The only ported vacuum port is on lower throttle plate on passenger side of carb but it is modulated meaning the amount of vacuum tapers off as the throttle plates continue to open because it’s used for the EGR valve. I just went through this with Cliff Ruggles.
That's correct.Lars