Quadrajet is WAY easier to make work right than a Holley. I would never have another Holley. Worthless crap that needs to be beaten to death. Horrible idle and part throttle circuits. You just don't know what you are doing with a Quadrajet and that is why you dislike them. I am willing to take a few months to get it right if that is what it takes. I like carbs I never have to touch after I get them set up and there is no Holley I can get 50k miles out of without any changes. I can and have done that with a Quadrajet in the past. I try to keep my cars low maintenance and do not want to constantly have to mess with them to keep them running. I also hate any and all chrome under the hood of anything I drive. Too much work to make it look right so my engine is a sea of black and is very hard to distinguish from stock so I never have to detail it.
yeah,EFI systems are a little out of my price range right now, and i like more old school technology so the carbs right up my alley lol i was actually looking into an edelbrock 750? ive heard lots of good about edelbrocks aftermarket stuff.
Quadrajets are trash my man. Good for stock to mild build. Other then that you cant get it right, and if you do it wont stay that way long. i would go with a holley/demon for your app. it will be MUCH more user friendly for you out of the box, with minor adjustments.
For all out racing Holleys/Demons are what to use, dont trash talk Q-jets if you dont know how to tune them!!i know of several guys running 11s-12s with Q-jets...The only good Holley that i know of is a double pumper nothing else!! Every car ive owned has been reliable, low emissions, and great mileage thanks to a properly tuned 750cfm Q-jet...
my 403 Olds pushed my cutlass into the low 13s while banging out 18mpg in the city and passing NE Super stringent emissions inspections... DO NOT KNOCK THE Q-JET!
85 Cut your initial post for 83Cut was outstanding. I can't verify it as I don't have the experience with these components but that kind of info is what makes these boards invaluable and our hobby better.
I have a FI GN & love FI especially for a tubo application. That said knowing what can be done with a well done Q-jet I can't see the expense of converting to an EFI on a naturally aspirated application as worthwhile. I applaud those that have done it just not worth it to me.
If I had a drag car big or small block I'd run a holley. If I had a strung out small block street strip car I'd run a holley. Anything short of that and both carbs being equally well set up the Q-jet hands down. The holley is easier to understand and tune but you are going to have to do it alot more often. The Q-jet will idle nicer, stay on tune MUCH longer, stay on tune through abrupt weather changes much better, provide better mileage, have almost FI like part throttle response and operation.
I sent my 800cfm electric choke Q-jet that I got off my junkyard Cadillac motor to The Carb Shop in Ontario CA for a stage II rebuild. (like JET provides only cheaper with better quality control & ACCOUNTABILITY if there is a problem) I gave them my motor & car specs. It came back just a tad rich (which is safe) has performed flawlessly for 9,000 miles ran a 3840 car through the 1/4 at 110 without missing a beat. Starts idles part throttle driveability mileage WOT no adjustments no repairs winter or summer. That would have never happened with a holley.
You have almost the exact same buildup I have, cam and heads...with Speed Pro forged pistons, Manley stainless valves and cam-matched springs...full MSD ignition (pro-billet distributor, 6AL, 8.5mm wires, etc). I am, however, using a Weiand Action Plus and a 795-cfm Q-jet.
The only thing I can say is that it's not 400hp, probably closer to 350-375. The cam really doesn't come on until 2200rpms or so, which is kind of a b*tch when it's in front of a 4-speed and just cruising around town. I'd DEFNITELY run a mild converter to make up for this, and a bit extra gear out back. I have a 2.20 1st gear ratio and 3.08s out back, and it's a PIG off the line, but charges hard around 3000rpms. The cam falls off pretty noticeably around 6200. I would also upgrade the rockers; the stamped steel self-aligning rockers kinda suck, but they do work. The Q-jet works great for this application; KILLER response and good mileage if I keep from opening the secondaries: 21mpg with the 3.08s at 65mph!
Car Craft did a very similar buildup, and they got 377hp and 412 lb-ft torque from the buildup, but with an RPM Air gap intake. But FYI: if you use an Air Gap intake (I had one before I got the Weiand), you'll have to cut a hole in your hood for air cleaner/carb clearance; they are TALL. Here's the link to the Car Craft motor:
Oh yeah...and in case you were wondering what th idle was like, well, with open headers and 800rpm, , it sounds JUST like the drum intro to "Hot For Teacher" by Van Halen! 😀😀😀
Oh yeah...and in case you were wondering what th idle was like, well, with open headers and 800rpm, , it sounds JUST like the drum intro to "Hot For Teacher" by Van Halen! 😀😀😀
The reason i said what i did about tha Q-jet was becasue i thought he was building a performance car for racing. If you want good gas mileage i guess a q jet is the way to go. But me, i am ALWAYS under the hood of my cars tinkering with diffrent set ups and tuning. Thats how i get my power, and holleys have never let me down.
85 Cut your initial post for 83Cut was outstanding. I can't verify it as I don't have the experience with these components but that kind of info is what makes these boards invaluable and our hobby better.
I have a FI GN & love FI especially for a tubo application. That said knowing what can be done with a well done Q-jet I can't see the expense of converting to an EFI on a naturally aspirated application as worthwhile. I applaud those that have done it just not worth it to me.
If I had a drag car big or small block I'd run a holley. If I had a strung out small block street strip car I'd run a holley. Anything short of that and both carbs being equally well set up the Q-jet hands down. The holley is easier to understand and tune but you are going to have to do it alot more often. The Q-jet will idle nicer, stay on tune MUCH longer, stay on tune through abrupt weather changes much better, provide better mileage, have almost FI like part throttle response and operation.
I sent my 800cfm electric choke Q-jet that I got off my junkyard Cadillac motor to The Carb Shop in Ontario CA for a stage II rebuild. (like JET provides only cheaper with better quality control & ACCOUNTABILITY if there is a problem) I gave them my motor & car specs. It came back just a tad rich (which is safe) has performed flawlessly for 9,000 miles ran a 3840 car through the 1/4 at 110 without missing a beat. Starts idles part throttle driveability mileage WOT no adjustments no repairs winter or summer. That would have never happened with a holley.
The possible reason for the richness is the choice of a 500 Caddy core. From what I have read, the idle feed restriction is set specifically for the engine size from the factory and using one off a 500 on a 350 would therefore make it rich. This is the same problem you would have on a Holley 750 vacuum on a 350 and why people restrict the passage with a small piece of wire to lean it out on that carb. It was originally spec'ed for a 396/375 hp engine so the loss of 46 ci makes it too rich. It is therefore critical to get a carb that originally on an engine of similar displacement to the one you plan to put it on. There is a way to change it, but I do not know the correct procedure and can't give a recommendation. I got mine off a 350 powered 1979 Chevy Van. It took me 5 months to find a core I deemed acceptable ( good shaft bores, engine size, throttle bellcrank), but it runs great with the original primary calibration. I am still working on the secondaries as the rods I am using are too rich, but I have to wait until I have a floor under the driver's seat to work on it again....
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