edelbrock vs quadrajet

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nomadsland71

New Member
Hello everyone, I've been debating on what carburetor to get for my engine set up to achieve the best gas mileage for long drives and still have enough power to turn the wheels. Been looking at edelbrock 750 or quadrajet 800 cfm for my 454 with a little better then stock cam with edelbrock rpm air gap intake and will be running headers on my 27 t coupe. I know 454 and gas mileage, whats that...lol. Any help would be appreciated. Thanks
 
Ran a 454 in our 39 Chevy tudor for 25 years. 600 cfm electric choke Edelbrock ran the car just fine. 750 cfm ok for race motors but way too much for mostly a stock engine.
With 3:08 gears, and 3400 lb car achieved 18 mpg if I behaved myself and ran high 14's at the strip.

Running the 600 wasn't about being cheap about paying for gas but needed the range between fuel stops, as the car
made 4 trips to Bonneville Salt Flats using mostly two lane blacktop to do it.

I think the Air gap manifold would have to go and install a performer intake as well.
 
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I have found that the Air Gap manifolds are alright for higher r.p.m. but not much chop for economy and comfort for just cruising. As for the Edbrock Carb I have never had anything to do with them yet, but the Quadrajet is streets ahead of a Holley for economy and reliability.
 
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nomadsland71 said:
Hello everyone, I've been debating on what carburetor to get for my engine set up to achieve the best gas mileage for long drives and still have enough power to turn the wheels. Been looking at edelbrock 750 or quadrajet 800 cfm for my 454 with a little better then stock cam with edelbrock rpm air gap intake and will be running headers on my 27 t coupe. I know 454 and gas mileage, whats that...lol. Any help would be appreciated. Thanks
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Had good luck with Qjet thru the years If it is used make sure throttle shafts are not loose . They are very tune able to get faster secondary response as well .
 
Q-jet

Hiya Nomads:

I'll chock up a vote for the good ol' Q-Jet, they are great carburetors. I was forced to learn a thing or two about them several years back when I turned my old bracket car into an NHRA "Stocker" (in which I HAD to use a QJ, didn't have a choice). The QJ's only came in two sizes - 750 or 850 CFM to the best of my knowledge. When you get them set up correctly you'll have awesome throttle response and driveability, plus the vast majority of the time you will be running around on the primaries (which are much smaller than the secondaries - spread bore design). The Edelbrock is a square bore design and the primaries I think are a little bigger than the QJ primaries.

Regards,

Bert
 
If your looking for mileage , reliability, easy starts and tuning . anything but a carb. Lot of stand alone EFI out there . if its out of your comfort range Dave MacDonald in Newcastle is the guy to ask.
 
I'll vote for the Edelbrock. For all practical purposes it's an AFB updated. It uses an air valve secondary like the Qjet so it supplies the right amount of air almost all the time. It takes a little more than a Qjet to set up, but is very adaptable. I have two of them with progressive linkage on the 454 in my Marlin, 350 turbo, and 3.50 gears with 15 by 15 Micky Thompson tires, and can get 16 mpg on a trip pulling a half ton trailer.
 
I've got an Edelbrock 600 on my 409 Chevy, a 500cfm on the 52 with a 283 and a 600cfm on the 54 with a 351W. Right out of the box...no adjustments and great performance and mileage.
The 39 Chevy had an Edelbrock 600 since 1991 with a 454. Good performance and mileage......
 
For the best fuel mileage my vote is a QJ or a Carter Thermoquad if you can find one in good shape. The aftermarket Carter 9800 TQ is the best one if you can find one. It was made as a bolt on replacement for a QJ. Other than that a 650 Thunder AVS is a terrific street carb, They're so good I use two of them on my car!

Sheldon
 
....I think the Q-Jet was and is the best choice . They were good enough for the General from factory and fed many mighty GM V8's. When I built my 12.5 / 1 396 I used a 800 Holley spreadbore and it worked very well also . But a well tuned Q-Jet I think is still the best for stock/mild V8 for overall economy and performance.
 
I'm with the guys on the Q-jet. Have run several over the years.

The '33 with the crapped out 350 has a Q-jet which I think dates from 1978. I kept a very close check on the mileage on the trip from Golden to Anglemont and again on the round trip to Logan Lake. Had to, because the gas gauge doesn't work. It hasn't gone anywhere else yet.

So with a worn out motor, black air filter, filthy carb, terrible ignition and shot spark plugs, it averaged just over 18 mpg. That's with small tires and a 3.55 rear end. The manifold is an ancient Edelbrock CSB.

I expect a lot better than that with all the fixes that have been done.
 
OK I am with you on the QJ with the stipulation that they are great till you have to rebuild them,, (in my experience anyway) They work very well but (here anyway) I have to say finding anyone who can rebuild one and have it work well or sometimes at all.. well frankly doesn't happen! Sad to say I guess for carb guys around here, which brings up another point.. finding a carb guy at all these days is next to impossible! Me give me a holley.. I can rebuild one on the side of the road and be back up and running in no time.. QJ? yes a great carb but finicky it seems when rebuilt... again just my observation.

Bash
 
Bash and scratch said:
Sad to say I guess for carb guys around here, which brings up another point.. finding a carb guy at all these days is next to impossible!

Bash
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I guess you're right to a degree. Even trying to find a kit for a Q-jet isn't like it used to be.

I was in Lordco yesterday looking for a kit for the jet on the '33. Jeez, you'd think I was asking for a chunk of green cheese cut out of the moon!

But once you've done half a dozen of these carbs, they aren't terribly difficult. Granted, by comparison, the Holley is a piece of cake. But you just can't beat the sound of a jet when those big secondaries open up!
 
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cocobolo said:
I... But you just can't beat the sound of a jet when those big secondaries open up!
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Totally agree with you there.

Rebuilding a QJ is another story.

Holley's are ok depending what you get.

Edelbrock's ...this is the first one and came with the the '52.
600 CFM is Mismatched to the intake and the cam, hence need to upgrade to a 650CFM. Looked at re-jetting and installing stiffer pump springs but don't know if its still worth it in the long run.
 
Did some checking on where the Q-jet came from in the '33. Turns out it is from a 1979 Cadillac and was built on January 9, 1979.

The stamped number on the driver's side of the carb will tell you the date it was made, which plant and what car it was used on originally.

Q-jets came stock with widely differing CFM ratings. Some of the better ones are from Buick when they were pushing out their bigger motors, up to 800 CFM.

I think I will pick up a copy of one of the Q-jet books just out of interests' sake. I have to rebuild the one I have here anyway. It's been years since I did one, but I did lots back in the day. The old grey matter needs refreshing!
 
cocobolo said:
But you just can't beat the sound of a jet when those big secondaries open up!
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If you think one sounds good, you should hear a pair of them. Sounded almost like my old hemi opening up.
I experimented with a pair on a sbc offy dual quad intake many years ago.
Tried quadrajets, afb's and even an afb/thermoquad combo.
 
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