My 401 is currently setup with a Carter 4 barrel, but I am looking for a little more stock power. I hear the Quadrajet with matching intake with the ports cleaned up is the way to go. What should I expect to pay for the intake and Carb in usable condition and where is the best place to find them? Manifold #1372113 carb# 7026240 or 7041304 EBAY ? Any things to look out for, wrong number not the correct brakets etc... Also will the Carter Air cleaner fit a QJ? Thanks for your time.
The Carter and QJ have different throat sizes. The QJ is much bigger. I put a QJ manifold on my 62. I had to play with the throttle linkage a bit. The transmission kickdown too. Nothing major though. I've been told that some QJ throttles won't clear the manifold without a spacer. I'm not sure, mine worked fine (from 1978 Oldsmobile). "Correct" depends on what you want to do. I put an electric choke on mine. You'll need to rebuild it to Nailhead specs. Checkout Cliff's High performance. He's a good guy who can set you straight. All in all, I have been very happy with mine.
The regular aircleaner that fits the Carter will not work on the Q-jet. I have the whole lot up here, I'm not using it on my Electra, the carb while a total rebuild has something wrong with it and I haven't had a chance or the desire to take it apart. Might get to it this year. I'm asking $600 for it, but I'm in Canada and the works would likely cost $200 to ship to the US these days.
I'd recommend getting a 67 big block Q-jet. Bolts right on and allows the stock throttle linkage and kick down linkage to be used. It's a far cry better than the 66 carb. I had an NOS 66 carb and sold it and had a 67 GS400 carb built instead
the stock Q-jet intake does not flow any better than the stock square bore intake. the stock Q-jet has 725 cfm vs the stock carter at 575 cfm thats why more HP from a Q-jet . a 750 cfm edelbrock or any 750 cfm carb for that matter and a modified stock air cleaner with more air flow or open air cleaner will give you at least 25 HP increase.
Yes the 66 uses hot air from exhaust manifold. 67 uses a divorced choke. They make an electric conversion for the Q-jet
There was a vacuum secondary Holley 750 DP on a 63 Riv that I had switched from the original carb. It had a 1/2” adapter plate that allowed the the butterflies to open fully. The linkage for the dynaflow had to be fabricated, and revised after binding at WOT. To Joe’s point, it made a big difference in the responsiveness and a little rpm extension. Gas mileage suffered though, and it also required switching to an electric choke. Cheryl
not only electric choke requirement but also you won't be able to hook up the factory kick down and switch pitch linkage.
You could fab something up to work on the throttle arm for the switch. The dynaflow, as discussed in my first post, has similar linkage for the transmission connected to the carb and that linkage eventually worked with the Holley. The first attempt jammed the throttle at wide open until the angles were changed a little. I used that problem as an excuse after being pulled over for speeding one day. Even though it had been previously corrected, I told the officer I had feared for my life and had turned the key off to stop. I even showed him the linkage and said it jams sometimes: no ticket! Cheryl
We are talking about larger carbs on the Nailhead as it is the larger CFM carb that is the ticket: not necessarily the carb type. This was a point made earlier in the thread substantiated by my experience. That’s where we are now.
Also, the op may be able to save considerably on the expense of a rare qjet manifold and qjet carb by adapting a larger carb to his current manifold and make similar power. Cheryl
trying to say keep your old intake, buy a 750 edelbrock carb. get one of these from ebay. save on an intake plus not trying to use an old Q-jet carb thats 55 years old. Babeola like the cop story lol, on a edelbrock no adapter needed but holley yes you would.
Too bad you cannot buy the 6-2's he's talking about... OUT OF STOCK!! And I doubt it would be cheaper (intake $600 if available, each duce $200+ new, linkage, filters... $3000 minimum)... than a QJ with intake... But thanks for the info.. I read a lot of his info under tech info. the 800 AVS article was helpful. https://www.nailheadbuick.com/post/...vs2-to-the-57-and-later-nailheads-square-bore
lots of false statements in there. the ones that are true he learned from the hard work and money from other nail head guys.
