Waste wages.

[99xcss4]

ah nothing like that quadrajet moan I think thermoquads also did that

xc_hide_links_from_guests_guests_error_hide_media

there are aftermarket 4 varrel spead bore efi systems but they do not moan like the carbs kind of sad

xc_hide_links_from_guests_guests_error_hide_media

 

[HotWheelsBurban]

ah nothing like that quadrajet moan I think thermoquads also did that

xc_hide_links_from_guests_guests_error_hide_media

there are aftermarket 4 varrel spead bore efi systems but they do not moan like the carbs kind of sad

Put yer foot in the throttle hard, and ya get the slap back into the seat, and "Whaaaaaaaaa! Under the hood......

 

[99xcss4]

Put yer foot in the throttle hard, and ya get the slap back into the seat, and "Whaaaaaaaaa! Under the hood......

yup but you need one of these so you can hear it better and it also makes it more easy to here it sucking gas and maybe I am still too you but I like loud intakes https://www.summitracing.com/parts/knn-66-3100

 

[Road Trip]

I'm diggin' that stealth cowl induction,never thought of doing it that way. There's a good amount of high pressure air coming off the bottom of the windshield.

Clean and effective!!!

Yes it is! When I was young and impressionable I read an article where a Chevrolet engineer
was reinstalling one of these 'cowl plenum' induction setups feeding into the 2x4 Holley 4-bbl
setup atop the factory DZ302 crossram in a '68 Z28? Form follows function -- a thing of beauty.

Years later, while battling stoopid amounts of underhood heat after stuffing a hot 355ci SBC into
a mid-'70s Chevy Monza, I couldn't get the owner to put a hole in the hood, but I was able to
talk him into fabbing up a reasonable facsimile of that cowl plenum induction setup.

Not only did it fix the issues associated with feeding the carb with superheated air, but ducting
the air cleaner through the firewall & into the same space that the heater system drew in outside
air literally filled the interior with beautiful intake tunes through the air vents. First time passengers
in the car always commented on this sonic feature -- it is always that loud when you floor it? :0)

Here's some interesting tidbits:

* Only GM car that this came from the factory with this setup installed was the '63-only Impala ordered
with the 427ci Z11 motor. (A stroked 409 W motor.) Here's the one that Grumpy Jenkins used to
turn wrenches on:

You must be registered for see images attach

(credit: 1963 Chevrolet Impala with Z11 Drag Package)

It's a rare option, originally available over the dealership parts counter specifically for
'65-'66 Chevelles and '67-'68 Camaros. (The '69 Camaro got the cowl induction hood.)

And of course since we've posted a photo of a Mk. II BBC, we should round out this
post with one of these rare cold air intake options on a Mk. IV 396 in a mid-'60s Chevelle:

You must be registered for see images attach

Once you've experienced the thrill of driving a car that's pulling cold air from the plenum at the base of the windshield,
it's something you remember the rest of your life. Well, at least it's still a vivid memory for me ~4 decades later.

It looks like pure business, and sounds even better than it looks. Understated max-effort underhood bling.

EDIT: The primary theory of why these work was always blaming the high pressure air that stacks
up at the base of the windshield. But this only occurs at speed. On the other hand, depending upon the
difference between underhood and ambient temps, the improved trap speeds & lower ETs might have
more to do with the denser, cooler outside air vs feeding your engine air that's been heated by it's trip
through the A/C condenser & radiator, and also absorbing heat thrown by the exhaust system.

The generally accepted rule of thumb for horsepower gain is roughly 1% improvement for every 10°F drop. (!)
Food for thought -- dropping air inlet temps by 50+ degrees is not overstating the improvement this setup delivers.

Definitely let these photos roll around in the back of your mind. Functional cold air cowl induction
is right up there with beehive valve springs and titanium connecting rods. Not many people can
properly appreciate the difference...but the few that do, they appreciate it a lot.
:0)

 

[Scooterwrench]

literally filled the interior with beautiful intake tunes through the air vents.

Yeah I kinda thought that would be a pleasant side effect especially if you were to put it right in front of the vent stack.
I'm thinking of going straight back off the breather. I've got this theory that spinning the air in the breather is counter productive to forcing it down through the air horn,centrifigal force and the fact that air has weight and all that. On the other hand spinning the air will spin all the bugs out and away from the filter element.

 

[Scooterwrench]

Oh yes I do remember how cool and bada$$ the Quadrajet opened up, sounded on our square body trucks and Burbs.....I do love the sound of a V8 in the morning (or any time really!).

The Q-jet should be classified as a musical instrument.

Dammit! Now y'all are making me reconsider TBI. My 355 has a decent one on it now and I've got another one built and ready should this one wear out. And now I've got a WBO2 to dial it in to almost EFI economy.
Rrrrrr!

 

[wasted wages]

You must be registered for see images attach

started the tbi swap with a rebuild kit for the tbi. The kids play table is just about perfect for this lol.

 

[Road Trip]

The Q-jet should be classified as a musical instrument.

Scooterwrench, I happen to be in violent agreement with your statement. :0)

I still remember the first night I ever flipped the lid on the air cleaner atop a Quadrajet and went for a drive.
('74 454/Turbo 400 C20 8-lugger Camper Special.) Teenager Road Trip had goosebumps on his arms before the end of
the highway onramp. (Insert the Deep Purple song "Highway Star" being played on an 8-track here. :0)

Here's a photo showing where the source of where that bellowing intake roar originates:

You must be registered for see images attach

(credit: ebay auction for a NOS Quadrajet throttle plate.)

Check out those glorious secondaries. Twin 2 1/4" diameter throttles. Each one is the same diameter as a American billiard ball! (See attached.)

Over time, I've come to realize that my choices in life are driven by the associated sonics much more so than
most of the well-adjusted folks in the audience. :0) So when working on a Bucket List powerplant project,
(assuming all other things being equal) whichever solution is going to bring the most memorable intake tone
is the way that I can't help but choose.

Even if it means more fabrication/effort. Because a lot of my touchstone memories include stuff like an afternoon
thunderstorm at the Grand Canyon, the infrasonic rumble while riding in the Maid of the Mist at the base of
Niagara Falls, or the full-throated roar of a WOT Quadrajet on a recently rebuilt V8 on a perfect summer evening.

Fortunately, given how much hood clearance there is in our GMT400s, we aren't force to run a stock,
low-profile spread-bore intake manifold. So our choices are anything but limited for our engines.
(Endless Q-Jet intake possibilities) BTW, see attached for a couple of modern Q-Jet capable dyno-proven
front runners.

But in order to achieve that complex, layered melody that will bring back the memories of your misspent youth,
be sure to adopt a high performance, high rise dual plane intake, and avoid the sexier looking single plane offerings.
Not just for the better street-rpm performance. But to get that authentic tone. And if you believe this to be self-evident,
then you are done reading this reply.

**** (Optional Reading) ****

But if you are still wondering why I would use sound to eliminate the single-plane intakes from my Bucket List
Quadrajet-fed project engine? The answer will require a little math that will allow me to translate from motorhead
to audiophile.

Keeping things simple, let's look at the 3000 to 6000 rpm range.
This translates to a 50 to 100 crank revolutions per second.
And since it takes 720° to complete all 4 cycles, we will therefore have an intake stroke every 25 to 50 cycles
per second. (ie: 25 to 50 Hz)

If we communicate these intake strokes through a common plenum (either carb single plane or Vortec EFI manifold) then
the intake melody will be based off of these fundamental frequencies. (Note: Similar to the relative smoothness and
higher PRF (Pulse Repetition Frequency) of a single exhaust.)

And if you perch a square-bore Holley 4150 on top of this single plane intake, then the tone will be shifted higher,
partially because of the higher PRF from the single plane, and partially because the throttle bores are smaller,
causing the resonating tone to be at a higher audio frequency.

****

On the other hand, if you put a Q-Jet on top of a dual plane intake manifold, we now have two individual manifolds,
taking turns every 180° of crank rotation to feed the next cylinder in the firing order. So we end up with (2) intakes
running from 12.5 to 25 Hz, essentially halving the PRF. But there is a chorusing effect, because these intake tracts
alternate every 90° of crank rotation. (Similar to a true dual exhaust behind an engine with a flat-plane crank.) And
of course the larger the secondary throttle openings, the lower the resonant frequency of the air pulses passing
through. (Think carb design from a wind instrument perspective.)

Believe me, this sonic signature stuff is easier to pick out with the ears as opposed to trying to explain it via typing.
But after years of listening to all manner of intake setups on SBC/BBC engines, there *are* distinct sonic differences
between the main intake combos. In terms of personal preference, here's a list in order of increasing sonic excellence
for a street driven small block or big block Chevy V8:

* single plane intake fed by a square bore Holley
* single plane intake fed by a spread bore Q-Jet
* dual plane intake fed by a square bore Holley
* dual plane intake fed by a spread bore Q-Jet (lid flipped)
* IR (Individual Runner - Think max effort Can-Am big blocks.)
* dual plane intake fed by a Q-Jet drawing cold air from any of the cowl induction examples above. (!)

Given all of the above, I think that the Q-Jet is the affordable pipe organ of GM's induction setups. :0)

EDIT: Bonus reading. If you have ever sat in church and soaked up the sound of a large pipe organ...and
started wondering just how many cfm it took to drive the big bass pipes that shook the house of worship, then
you might also find the article associated with the last attachment of interest: (What size fan or bellows for a large pipe organ?)

 

[Jimmy D]

Put yer foot in the throttle hard, and ya get the slap back into the seat, and "Whaaaaaaaaa! Under the hood......

You know that's right! I've loved the Quad moan since the 60's. Pulling out and matting the loud pedal never gets old. I have a 69 C10 Chevy truck with a 358, Edelbrock intake, RV cam, 4:11 rear and my favorite carb, a Quadrajet 4 brl for sound effects. I've been rebuilding my own Quads since I was a teen. I swear I won't have any computer crap on this truck!

 

[Scooterwrench]

You must be registered for see images attach

started the tbi swap with a rebuild kit for the tbi. The kids play table is just about perfect for this lol.

Ha-ha,that TB ain't childs play but it ain't rocket science either. A little carb cleaner and purple power will make it work like new. You can pop the injectors open with a 9V wall wort and blow carb cleaner backwards then blow with compressed air. I've cleaned some that were completely clogged. Good time to install an adjustable pressure regulator.