Quadrajet to Holley Swap
#1
Racer
Thread Starter
Quadrajet to Holley Swap
I'm finishing up the 383 stroker build for my 76 and I'm thinking of swapping the Q-jet for a spread bore Holley carb. I would like to know exactly what is involved with this swap regarding the linkages and fuel inlet.
Last edited by ykf7b0; 07-08-2017 at 11:09 PM.
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73racevette (08-18-2017)
#5
Le Mans Master
Not much for the Holley 4175 650 CFM vacuum secondary Qjet replacement carb:
Just the fuel feed....everything else hooks right up including the throttle linkage..............
Apparently photobucket wants money now to subscribe to their site for 3rd party viewing of photos so for the time being no photos available......jerks!
Just the fuel feed....everything else hooks right up including the throttle linkage..............
Apparently photobucket wants money now to subscribe to their site for 3rd party viewing of photos so for the time being no photos available......jerks!
Last edited by jb78L-82; 07-09-2017 at 02:12 PM.
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ykf7b0 (07-09-2017)
#6
Le Mans Master
I had the double pumper version on mine for a while and I don't recall changing anything. Most quadrajet fans and traditional holley guys talk trash about them but they are really nice carburetors and perform very well. I like the double pumper better because vacuum carbs tend to be soggy and less crisp.
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ykf7b0 (07-09-2017)
#7
Burning Brakes
I recently replaced my quadrajet with a 6211 (really a 6212 with 6210 bowls).
The only real modification was to cut the throttle linkage bracket so that the mounting bolt on the drivers side was the only one used, and the alignment slot next to it.
Outside of that I run AN fittings. I can say this much, the fuel inlet is slightly forward of the qjet's, but in general its pretty close.
I will say this much... I like it. Im hoping you have an 800 spread bore as opposed to a 650.
The only real modification was to cut the throttle linkage bracket so that the mounting bolt on the drivers side was the only one used, and the alignment slot next to it.
Outside of that I run AN fittings. I can say this much, the fuel inlet is slightly forward of the qjet's, but in general its pretty close.
I will say this much... I like it. Im hoping you have an 800 spread bore as opposed to a 650.
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ykf7b0 (07-09-2017)
#8
Le Mans Master
I had the double pumper version on mine for a while and I don't recall changing anything. Most quadrajet fans and traditional holley guys talk trash about them but they are really nice carburetors and perform very well. I like the double pumper better because vacuum carbs tend to be soggy and less crisp.
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ykf7b0 (07-09-2017)
#9
Team Owner
Since you still want a spread-bore carb, the best and least expensive thing to do is to get your Q-Jet rebuilt [properly] and reuse it. I see no advantage to swapping the Q-Jet for a spreadbore Holley.
#10
Melting Slicks
I had a Holley spreadbore (Model 4165, List 6210-3)on mine. Stock linkage and fuel line work fine but you will have to make a new choke rod.
But I had a fuel slosh problem with the Holley I was never able to resolve. The engine would die under hard braking. I went to a Lars rebuilt Quadrajet (pictured on Lars' test engine below) and have no regrets. More responsive and no more fuel slosh problem.
But I had a fuel slosh problem with the Holley I was never able to resolve. The engine would die under hard braking. I went to a Lars rebuilt Quadrajet (pictured on Lars' test engine below) and have no regrets. More responsive and no more fuel slosh problem.
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ykf7b0 (07-09-2017)
#11
Had a 1976 L-82, 4-sp
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Royal Canadian Navy
I have had my 4175 since 1985 and really like it...the secondaries open at about 3,000 RPM when I need them and the power is very progressive with zero bog to 6,000 RPM...I use the lightest secondary spring. Does the double pumper version bog at all if you hit the throttle hard? I am running a 68 main jet but may need more like 70+.
#12
Tech Contributor
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...and not just a little bit of money. They want $500 for the "privilege" of linking your photos to a forum posting. They have blocked all my photo posts for being a gross violator of their "linking policy." Jerks.
#14
Safety Car
carb. cable and bracket work just fine as is. so does the choke linkage.
my best advice is to ensure you use the the original style,
1/4" thick gasket for temperature isolation of the carb.
to prevent fuel from boiling in the carb.
Holley Spreadbore, original throttle linkage.
my best advice is to ensure you use the the original style,
1/4" thick gasket for temperature isolation of the carb.
to prevent fuel from boiling in the carb.
Holley Spreadbore, original throttle linkage.
Last edited by 69Vett; 07-10-2017 at 11:30 PM.
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ykf7b0 (07-10-2017)
#16
Safety Car
None. When you post or reply here there is a small yellow box just above where you type in your message with what looks like mountains at the bottom. It is for inserting images right off the photos on your computer and works really well.
#18
Burning Brakes
For me, the "hump" in the middle of the throttle bracket (that goes over the vacuum port for power brakes on quadrajet) wouldn't fit with the Holley, so it had to be cut. You'd never know by looking.
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ykf7b0 (08-17-2017)
#20
I am getting ready to rebuild my engine and have been thinking about using one of the throttle body fuel injection systems instead of the stock carb. Money for new carb could go to cost of the system. Has anyone been using these trying to improve the drive ability of the car?