hey grumpy? how about 6 duces?

[grumpyvette]

hey grumpy? how about 6 duces?, I found an intake and carbs at a yard sale priced reasonably, should I pick it up?

the carbs are available,for the multi 2 barrel intake manifolds of various designs, but they are expensive and theres NO PERFORMANCE ADVANTAGE TO USING THEM, as the more modern carbs atomize fuel far more effectively ,they might be fine on a show car for looks, but I don,t think its a good idea on anything you want to drive regularly, EDELBROCK,MAN-A-FRE AND OFFANHAUSER ALL USED TO SELL THESE STYLE INTAKES, THEY don,t generally produce nearly the hp a good dual quad or single quad intake can and require far more effort to tune, by todays standards the older designs are archaic and for period correct show cars only
yes they can be made to run surprisingly well IF you understand how and want to take the effort to do in correctly
READ THIS LINK
http://garage.grumpysperformance.co...-x-1-how-do-you-set-this-up.11688/#post-54747

http://www.jenvey.co.uk/
BTW IF YOU THINK OVER CARBING AN ENGINES A HUGE CONCERN,HERES A VIDEO OF A GUY RUNNING 4 750 quadrajet 4 barrel carbs on a car engine, and once tunned for the application it seems to run decently

the old 4 deuce and 6 deuce intakes look impressive but rarely run as well as dual quads, dual quads on a well designed tunnel ram intake , or if you must have multi carburetors Id suggest the newer 4 weber intakes which are all far easier to tune
even the older constant flow mechanical fuel injections far better

RELATED THREAD
viewtopic.php?f=55&t=4302&p=12406&hilit=intakes#p12406

viewtopic.php?f=32&t=3916&p=10420&hilit=intakes#p10420

Pontiac 6 deuce intakes were manufactured in several versions, like the two design,s posted below, the log style manifolds were also made for caddy oldsmobile and ford
the early log single bank design was common but rarely worked very well as the runner length was very short

the later cross ram versions worked far better
IF YOU KNEW HOW TO TUNE

http://www.thecarburetorshop.com/

Addition of tripower to a V-8 engine

General

One common “accessory” to a “hot rod” engine set-up is tripower. This is generally done for “looks”, although a few misguided individuals still make the addition for performance. In truth, a “perfect” tripower will never compete (on an 8 cylinder engine) with a properly sized single four-barrel, or better yet, a properly sized dual four-barrel setup. But the reason for the article is not to discuss performance, rather as an attempt to help those who wish to add tripower to their engine.


There are basically 4 methods of adding tripower to an engine. From easiest to most difficult, these are:


(1) If available, install a complete original factory tripower

(2) Install an aftermarket intake with original factory tripower carbs from a similar displacement engine

(3) Install an aftermarket intake and non-tripower carbs with solid linkage

(4) Install an aftermarket intake and non-tripower carbs with progressive linkage.


Unless you opt for option 1, the enjoyment of your tripower will probably be in proportion to the amount and quality of research you do PRIOR to its purchase!


Installing a complete original factory tripower

This is the easiest method of acquiring tripower. All it requires is money. BUT, all of the engineering has been done for you. Simply find a good reference on your engine, and make certain that you have updated the entire engine to the tripower engine specifications. This could include cylinder heads, camshaft, distributor, and exhaust manifolds. If all components are updated, simply find a reliable source for the complete tripower, rebuild it if used, and bolt it on.


Installing aftermarket manifold/original tripower carbs

This is the second easiest installation. BUT some engineering is necessary. One should select a factory unit from a very similar in displacement engine. Thus if one has a 350 Chevrolet, a factory Chevrolet 348 tripower would make a good donor. If one has a 390 Ford, then original tripower carbs from a 389 Pontiac would be a good choice.


Assuming you acquire carburetors of the proper size; your most difficult issue now will be linkage. Many original equipment tripowers used vacuum linkage, simply because it was much more reliable FOR NON RACE APPLICATIONS than mechanical linkage. However, vacuum linkage today can be difficult to obtain, and incredibly expensive. Thus, many will opt for mechanical linkage due to financial consideration. If you should decide to use mechanical linkage; TAKE A LOOK AT THE WAY THE FACTORIES PRODUCED MECHANICAL LINKAGE! Since these units were originally designed for progressive linkage, progressive is what you will need to use. The big issue is with how the links are affixed to the throttle arms. Take a look at a typical Pontiac link from the front carb to the rear carb. The arm on the rear carb will have a round hole in which to attach the link. The front carb has a horizontal slot. This slot is necessary to compensate for the coefficient of linear expansion. When installing the link, the link should be placed in the round hole of the rear carb and the retaining clip installed. The link should now be installed into the horizontal slot of the front carburetor, and the link bent as necessary such that the link is installed in the center of the slot. The retaining clip should now be installed. FAILURE TO MAKE THIS ADJUSTMENT WILL RESULT IN ONE OR THE OTHER OF THE END CARBS ALWAYS CRACKED OPEN, AND EITHER A POOR OR IRRATIC IDLE CONDITION!


Next comes fabrication of fuel lines. At various times, different manufacturers have used steel, aluminum, and copper. We would suggest using steel. Make sure you double flare the tubes when fabricating the lines. Aluminum or copper may be used, however consider that flaring will “work harden” the tubes, and vibration can result in failure at these locations. Also, tightening the lines adds stress to the flares. We suggest NEVER reusing aluminum or copper lines. Thus should you need to rebuild the carbs, you should replace the lines.


Aftermarket air cleaners can be challenging; however, the reproduction Ford air cleaner can be purchased with the bottom unpunched, and a ready supply of filters is available. Should you go this route NEVER punch the bottom until the unit is installed on the engine (or consider the position of every other item in the engine compartment so you don’t punch in the wrong place). The last unit I did had to be offset approximately 1 inch to clear a coil bracket.


Installing aftermarket intake/non-tripower carbs with solid linkage


This installation is much more difficult than the section above but MUCH EASIER THAN THE INSTALLATION IN THE SECTION TO FOLLOW!


The first AND MOST IMPORTANT issue here is selection of the carburetors. Contrary to popular belief, three 250 CFM carburetors will not flow 750 CFM. What they will flow will depend on a multitude of variables, including the size of the carburetors, the size of the engine, and the efficiency (or lack thereof) of the intake manifold. What carbs to use? This becomes a matter of experience; but generally three from an engine of approximately three quarters size of your engine should work. Thus, if you have a 400 Ford, three carbs from a Ford 289 or 302 might suffice well. ANOTHER KEY IS ALL THREE CARBS SHOULD BE IDENTICAL BY TAG NUMBER! Just because the carbs fit the manifold is absolutely no guarantee that they will function well.


Linkage will require fabrication. Since all three carburetors will be functioning simultaneously, the paragraph in the above section concerning the coefficient of linear expansion does not apply.


If you need a choke, choke all three carburetors.


Use the idle circuit on all three carburetors.


CARBURETORS MUST BE SYNCHRONIZED.


Installing aftermarket intake/non-tripower carb and progressive linkage


This is by far the most difficult installation, and, ironically, the type installation often done by novice mechanics. Because of all of the issues involved in trying to make this setup work, WE WILL NOT BUILD THIS SETUP FOR ANYONE!


For those who have lots of free time, and a good automotive machine shop at their disposal, here are some guidelines on how to proceed:


The first issue is carburetor selection, and the selection of the center carburetor is critical. Since the center carburetor will be responsible for idle fuel, low speed, fuel, and fuel at cruise; THEREFORE, THE CENTER CARBURETOR MUST BE FROM A COMPARABLE SIZED ENGINE. Lets say you are putting a tripower on a 390 Ford. I don’t care what bolt pattern you have, a Stromberg 97 or a Holley 94 is not going to work for the center carburetor. You need an original carburetor from a 390 Ford! Failure to provide the proper sized (internally, not bolt pattern) carburetor will lead to idle and low-speed issues and may lead to a failed engine!


End carbs should be similar in size to the center, and while they may differ in identification number from the center, the front and rear should match each other.


As to the end carbs, MACHINE WORK IS NECESSARY ON VIRTUALLY ANY MODERN CARB!


Why, well, consider this: the throttle plates in end carbs MUST completely close and seal. Throttle plates in a single two-barrel application never completely close. Thus the manufacturer uses a thin throttle plate (to minimize air disturbance) and they close at a very small angle (to maximize adjustment range). To seal the throttle plates, the manufacturer used a much thicker plate on factory end carbs, and closed them at a much greater angle. Trying to force the thin plates to close and seal will result in the plates either not sealing or sticking in the throttle bore, and never opening.


Thus, to make a non-tripower modern carb function as a tripower end, one must first machine thicker throttle plates, and then machine a new throttle shaft to accommodate the thicker plates.


Yes, I am aware that there are some aftermarket throttle bodies available for Rochester 2-barrel carbs. However, the ones I have seen are aluminum. Virtually every carburetor that comes into our shop with an aluminum throttle body REQUIRES bushing. Think about Q-Jets, Stromberg WW’s, Carter BBS and BBD carbs. They all require bushing the first time they are rebuilt. The only exception seems to be the Carter AFB and AVS carbs which have a long bearing surface, and are deliberately set up loose (0.016~0.022 inch) rather than other carbs which are set up at 0.004~0.006. Maybe someone is now producing throttle bodies from cast iron, or installing bushings in the new aluminum throttle bodies, but if so, I am unaware of them.


Also, Rochester used at least 15 different throttle body gaskets on both the two common (large and small) Rochester 2-barrel carbs. This is because 1 size DOESN’T fit all (if you don’t believe me, try walking a mile in your spouse’s shoes)! The aftermarket throttle bodies may (or may not) work with the carbs you selected.


Idle circuits should be completely removed and plugged for end carburetors.


Power valves (if present) should be removed from the end carburetors. Since the end carbs are “dumper” carbs, trying to make the power valve function is just added complexity. Figure the amount of fuel which the power valve adds to the main metering circuit, and increase the main metering jets to provide this fuel.


Chokes are not necessary on end carbs using in progressive linkage setups, and should be removed. If an automatic choke, remember to plug the vacuum port supplying vacuum to the choke. Remove the choke butterfly and shaft. Plug the mounting holes for the shaft using aluminum drive plugs.


Once you have selected the carbs and modified the ends you can refer to previous sections for linkage (see factory progressive), fuel lines, air cleaners, etc.


You still have to calibrate the carbs. To do this, fabricate block off plates for the end plenums of the manifold, and install the plates, not the end carbs. Calibrate the center carb to run the engine up to about 500 RPM more than your normal cruise. Then remove the block off plates, and install the end carbs. Now calibrate for wide-open throttle. If your end carbs are machined properly, there will be no degradation of idle or low speed performance when the end carbs are installed. If degradation occurs, your end carbs need more work.


Good luck.

 

[grumpyvette]

Ive had many guys ask why not run three deuce intakes,well, they can and do produce good power when PROPERLY TUNED but, by today's standards, they are a bit behind the times in that the intake designs and fuel metering lack the fine tune consistency and fuel distribution of the single and dual quad intake and carb designs, I find the single quad and dual quad intakes are far superior in most cases
http://www.cranescorvette.com/tri_powers.htm

http://tech.corvettecentral.com/2015/11/67-69-tri-power-carburetor-tuningtroubleshooting/

67-69 Tri-Power Carburetor Tuning/Troubleshooting

What is your first impression upon seeing all these carburetors in a row? Sheer terror or wondering why they would do something that crazy? A few of us actually must have them. When the carburetors are set up properly, the feeling of an additional four barrels opening is exhilarating. The acceleration rate is similar in a Corvette with a supercharger or nitrous.

The trick is keeping clean fuel in three carburetors on a vehicle that is rarely driven. Depending on the length of time between run intervals, fuel tends to evaporate. In some climates, light solvents will distill out, leaving a gooey mess. Water condenses in empty or low tanks, so check before adding any fuel.

All tri-power cars have tanks that allow visual inspection of fuel quality. Before you start any tuning or troubleshooting, make sure the fuel is still volatile; it shouldn’t smell like varnish. Check for water at the bottom of the tank with a flashlight. You can usually see water as the car is pushed side to side. Water puddles in the tank ribs and looks like bubbles moving across the bottom.

While checking the tank, inspect the strainer (CC# 362209) pushed onto the fuel-sending unit’s 3/8 suction tube. If you have an original strainer, it is most likely disintegrating and dispersing particles through the fuel system, filling the filter with junk. Be sure to inspect your gas tank meter gasket too (CC# 362207).

Installing a 3/8 in-line fuel filter before the fuel pump is a great idea. Fuel pump check valves don’t like debris passing through them. The check valves will hang open and the fuel pump will stop working. Since the top of the Corvette fuel tank is the same level as the carburetor the engine will run decent at low speed and idle even when the fuel pump is not working.

It’s a good idea to add octane additives (CC# 351094) for better performance and low speed throttle response. If you have an original engine with soft valve seats, you should also use a lead additive. It’s common to find excessive fuel in the crankcase, so check the oil for fuel loading. Oil dilution will wash the rings of lubrication and cause extreme wear that’s dangerous. Holding a match to the dipstick after pulling it out will tell the tale. If the match lights the oil, fuel dilution is excessive.

Trying to avoid fuel leaks with all the lines and fittings can cause severe anxiety. We apply Teflon tape to the lines at the fitting area. This allows tightening the fittings against the lines with minimal line movement. Care must be taken to keep the Teflon tape out of the carburetor. Don’t put any tape on the seat portion of the line at all.

While checking fuel and oil condition, check the hoses. Fuel hoses dry out and crack, eventually causing leaks. Hoses can also crack internally to allow rubber particles to course throughout the system. Rubber particles cause erratic carburetor fuel bowl levels and unexplained flooding. These particles stick to the needle and seat, allowing fuel to flow uncontrolled into the bowl.

With the engine running the fuel level at each carburetor should be adjusted. Remove the fuel level sight plug and rock the car to see if any fuel spills out. Fuel should be at the bottom of the sight plug threads. It’s a good idea to have a rag under the carburetor bowl to soak up the excessive fuel. If the fuel runs out immediately the float level is too high. Be careful when adjusting the float level because fuel will spray out of the adjuster nut and screw.

The next step is to ensure correct fuel pressure before condemning the carburetor or adjustments. Low fuel pressure causes hesitation and “sag” under acceleration. It is most noticeable in high gear under heavy loads. High fuel pressure can occur if the fuel return line is crimped or full of debris. Carburetor flooding and uncontrollable, overly-rich fuel conditions will result.

With the engine idling there should be no fuel visible in the venturi booster area. Carburetor idle circuit fuel is metered to the engine below the throttle plates. If you see any white smoke billowing out of the carburetor with the engine off there is an internal fuel leak.

It’s common to find incorrect hoses at the fuel pump. Use only the O.E. style hoses (CC# 352353) to avoid fuel hose crimping. The close proximity of the lines to the pump will not allow universal fuel hose usage.

If you find an internal fuel leak on the outer carburetors check the metering plate for warping. We’ve found many warped metering plates along with corroded carburetor main bodies due to water in the fuel supply. If the carburetor main body has corrosion it most likely will require replacement.

Many cars exhibit poor running conditions because the fuel filter (CC# 351293) is full of debris. Although it is often last checked, it is one of the easiest. You would be surprised how many particles will pass through the O.E. fuel filter. Tap on the fuel inlet side of the filter to see how many particles come out. If you find a lot of debris coming out of the filter, it is a good idea to find the source.

Lay a straight edge across the metering plate. If the plate allows you to slide a .005 feeler gauge between the plate and straight edge you’ve got problems. In some cases the metering plate can be filed flat. Consider a replacement metering plate if the warping is severe.

Here are a few tips that pertain to all Holley carburetors. Finding the fuel/air mixture needles adjusted correctly is rare. The needles are always adjusted too many turns counterclockwise (too rich). Usually, one to two turns of the needles out from their seat is the maximum number necessary. There is a balancing act between idle speed and fuel mixture; in most cases the fuel mixture and idle require small adjustments to obtain the correct setting.

Once the engine idle speed is below 1,000 RPM the fuel/air mixture needles can be adjusted. Turning the needles clockwise should slow the engine down and shut the engine off. An internal fuel leak is occurring if turning the needles into their seat doesn’t shut the engine off. Turning the needles counter-clockwise richens the idle mixture. The needles should be turned in until the engine speed drops, and then backed out slightly.

Adjusting the fuel mixture needles too rich causes excessive fuel consumption and lazy low speed performance. Spark plugs are fuel-fouled from all that extra fuel. Adjusting the fuel mixture needles lean causes stalling and rough idle. Keep in mind, the 435 horsepower cam is not going to idle smooth but it should have a rolling idle.
Once the idle speed is adjusted the throttle linkage should be adjusted so that the throttle plates are fully closed at the outer carburetors. The throttle should be opened fully and closed with the engine off to make sure the linkage doesn’t bind.

To sum things up, we need clean, volatile fuel and adequate fuel pressure before making any adjustments. If the carburetor is working correctly, worst case scenario would be to start all over by turning the fuel mixture screws into their seat and then backing them out two turns and readjusting. Remember to make small changes and see what changes occur. Record the adjustments in case you need to refer to them later.

Related Items

• 152206 … 3×2 Carburetor Gasket Set
• 352063 … 3×2 Carburetor Gasket (Base to Intake)
• 352148/352085 … Carburetor Rebuild Kits
• 352135/353076 … Intake

3×2 Tri-Power Corvette Carburetor/Intake Manifold Part Number & Applications
HOLLEY CARBURETORS
(1967)


400 4-spd ctr 2300C R3660A 3902355

frt/rr 2300 R3659A 3902353
400 auto ctr 2300C R3888A 3909872

frt/rr 2300 R3659A 3902353
435 all ctr 2300C R3660A 3902355

frt/rr 2300 R3659A 3902353
(1968)


400 4-spd ctr 2300C R4055A 3925517


2300C R4055-1A 3940929

frt/rr 2300 R3659A 3902353
400 auto ctr 2300C R4056A 3902516


2300C R4056-1A 3940930

frt/rr 2300 R3659A 3902353
435 all ctr 2300C R4055A 3925517


2300C R4055-1A 3940929

frt/rr 2300 R3659A 3902353
(1969)


400 4-spd ctr 2300C R4055-1A 3940929

frt/rr 2300 R3659A 3902353
400 auto ctr 2300C R4056-1A 3940930

frt/rr 2300 R3659A 3902353
435 all ctr 2300C R4055-1A 3940929

frt/rr 2300 R3659A 3902353
ALUMINUM INTAKE MANIFOLDS
(1967)
400 hp 427 engine 3894382
435 hp 427 engine 3894374
(1968)
early 400 hp 427 engine 3919850
late 400 hp 427 engine 3937795
early 435 hp 427 engine 3919852
late 435 hp 427 engine 3937797
(1969)
400 hp 427 engine 3937795
435 hp 427 engine 3937797
435 hp & ZL1 427 engine 3933198
Story and photos courtesy Chris Petris

well theres several reasons but the main one is that theres far better quality and a much larger selection of good duel quad intakes and theres a better selection of carburetors that function well in dual quad arrangements, most three deuce set ups don,t have the total flow, intake runner flow or direct inline flow that the best dual quad and tunnel ram intakes have

viewtopic.php?f=55&t=444&hilit=dual+quads

YOU Also have at least a few big block EFI, and weber carb intakes that will fit under hoods on some cars

Id also point out that, in my experience, A properly set up dual quad intake and carburetors can make both better power and get better mileage than three deuces on most engines
now thats, obviously going to take a bit of explanation for those guys not familiar with how both systems work, and it assumes both systems are tuned to max efficiency.
on the older muscle car tri power set-ups ROCHESTER and STROMBERG carbs were common , neither of those carbs flows nearly what the modern Holley two barrel carbs are capable of, and neither carb can be used to produce near the power the current Holley carbs can,

factory big block three deuce intake
http://www.vintagespeed.com/carbs.htm

ok a three deuce or tri-power system has a center carb that controls the low speed intake air flow and , and lower mid rpm air flow rates the two outward end carbs act like the rear throttle bores on a 4 barrel intake, but use 4 throttle bores that open simultaneously to supply extra fuel/air as the center carb reaches a preset limit on the linkage, usually at about 1/2 throttle on the center carb, the two end carbs start to open and by full throttle all six venturies are wide open.

http://www.cranescorvette.com/tri_powers.htm
JEGS SB-Chevy 3-Deuce Intake Manifold and Carburetor Package combine nostalgic looks with modern features. The precision- cast aluminum dual plane, medium rise intake manifold is powder coated in a high gloss finish for incredible looks and durability. The 2,500 to 6,000 RPM manifold is topped off with three purpose-built 2-bbl Holley carburetors. A single fuel feed line is all that is required. The progressive linkage connects and controls the carburetors. The center carb is 350cfm with an electric choke and is used at idle and cruising speeds. The front and rear carbs are 325cfm that are ready to jump in and throw you back in your seat when the power is needed. The package is finished off with hand polished air cleaners with serviceable elements. Designed for use with 55-85 style cylinder heads.

NOW the outer carbs can be larger or smaller in capacity, but a 350cfm center carb and two 350-500cfm outer carbs are common on modern set ups, the older muscle car tri power carbs Rochester 2GC (small 1-7/16" bore) for #5419, Stromberg, Holley, were usually MUCH SMALLER
but the end result is that you either run on two small venturies at part throttle or two small and usually 4 larger venturies at anything more than 1/2 throttle which works well for foot on the floor launches but the transition requires a long high volume accelerator pump shoot to cover the effect of that sudden increase in air flow and resulting drop in manifold vacuum.
in effect you have two stages,with three deuces. low speed with high air speeds in the intake plenum, or WOT with a large surge of extra fuel & air, while a properly set up dual quad set-up has FOUR smaller progressively increasing flow stages making controlling the air fuel ratio thru the transition both easier and more precise.



dual quads can and usually are set up so that the back or rear carb primaries are the first stage at about 1/3 throttle the front carbs primaries start to open, at about 1/2 throttle the rear carbs secondaries start to open and at about 5/8 throttle the front carbs secondaries start to open, the result is a much more progressive and smooth transition and more precise control on the air/fuel ratio entering the engine, 4 separate stages with each stage having adjustments and jetting

OFFY BELOW [/b]
http://www.grumpysperformance.com/ofy11.jpg
http://www.grumpysperformance.com/ofy22.jpg
[IMG]http://www.grumpysperformance.com/manifoldmu1.jpg

you want to keep in mind the vast majority of people CAN,T TUNE DUAL QUADS OR THREE DEUCES WORTH CRAP, so most magazine test results that show a single 4 barrel being superior to dual quads have results more to due with a lack of correct component selection or tuning skill that true intake potential

http://www.hotrod.com/techarticles/engi ... _shootout/

viewtopic.php?f=55&t=444&p=10794&hilit=dual+quads#p10794

viewtopic.php?f=55&t=10747&p=46941&hilit=dual+quad+pontiac#p46941

viewtopic.php?f=55&t=444&p=5682&hilit=+dual+quads#p5682

viewtopic.php?f=55&t=6803&p=42536&hilit=street+demon#p42536

http://www.summitracing.com/parts/dem-1901

http://www.summitracing.com/parts/dem-1901 (625cfm) (CHEVY TRANS LINKAGE)

http://www.summitracing.com/parts/edl-7522

I can,t help thinking that twin thermal street demon 625cfm carbs on a big block might be fun to experiment with and tune as theres obviously some potential there for a lower (non- tunnel ram) style intake.
theres little doubt that the combo of the newer carbs and the intake flow well, as Ive seen a few guys using edelbrock 500 cfm dual quads on that BBC intake reach 570 plus hp on what were basically fairly mild 496 cubic inch engines built with mostly reworked O.E.M engine components with reasonably mild cams and compression compatible with crappy pump octane gas, using an out of the box intake manifold, and I've seen the intakes mildly ported so they flow noticeably more air, now even the single 625 cfm carb can support 500 plus hp, so at least in theory dual quads could easily support 700-800hp or more without tapping near the ported intake manifold's flow potential , with the twin carbs after proper tuning.
which at least in my eyes means it might provide both a visually impressive intake set up and a functional induction system that might serve as a basis for an old school looking hot rod.

yes there's zero doubt that a true tunnel ram has some advantages in flow rates and potential power curve,and there's no question the dual quad dual plane design gives up some flow to the more direct and straighter runner design of the taller intake, but many guys are less than over joyed with the idea of cutting a hood and installing a sight obstructing higher hood scoop or allowing the taller tunnel ram intake to stick out of the hood.

 

[grumpyvette]

http://www.summitracing.com/search?keyw ... =Ascending

summit sells the carbs and intakes youll need if you want something that looks old school, but at $400 for each carb plus the intake and knowing that theres more effective systems available...??

 

[Grumpy]

http://vintagespeed.com/

http://hotrodcarbs.com/store/tri-power-intake-manifolds.html

http://dickshotrodcarbs.com/carburetorgallery.html

http://www.weinlemotorsports.com/page.php?page=Custom-Built-Intake-Manifolds

 

[Grumpy]

Hey guys, I have a Rochester 4 deuce setup on my 32' 5-window and am having a hell of a time getting it to run well. Have gone through a ton of plugs as it doesn't take too long to foul them. The car is running way rich, especially at idle. Looking for suggestions on how to tune these properly rather than just cranking the mixture screws in and out. I've read a vacuum gauge is the proper tool to use, however what would be the best procedure with this setup as all four carbs are sinked together (none are slaves).

pictures of the intake would help here.
yes there's several far different intake designs
and yeah it does affect the way the carbs get set up
it would also help if we knew what model Rochester carbs were dealing with ,
and the fuel pressure,
multi carb intakes can be tuned it just takes consistency between the carbs jets, selected float levels, fuel feed and linkage adjustments

https://www.ebay.com/itm/Stromberg-Carburetor-97-Style-Speedway-9-Super-7-Carb-/261842745890

The Carburetor Shop LLC

a lot of this links info is about balancing two throttle bodies but a similar process is used to tune/balance flow with 4 dueces

http://garage.grumpysperformance.co...sfire-vette-won-t-run-right.10096/#post-39710

heres a picture
as previously stated,previously, start with setting all the float levels and adjusting the throttle linkage so the blades are all closed, at idle, consistency is critical
Id suggests you verify the jets are consistent as well.
there should be slight minimal slack in the carb arm linkage, and
before anyone asks,
no these old multi carm 4-6 deuce log intakes that were popular in the early 1950s ,
won,t run nearly as well as a properly set up dual quad or tunnel ram or cross-ram dual quad carb set up, but yes they can be tuned and made to run decently

Its been my experience that a properly set up, dual quad intake (tunnel ram)
or a few crossram designs will generally marginally outperform most single carb intakes, the single carb designs are far easier too tune unless your experienced

one reason a properly port matched tunnel ram intake flows efficiently is a strait path to the intake valve, in the cylinder head from the plenum

http://garage.grumpysperformance.com/index.php?threads/dual-quad.11867/#post-56263

http://garage.grumpysperformance.com/index.php?threads/will-dual-quads-work-ok.5888/

http://garage.grumpysperformance.com/index.php?threads/tuning-a-tunnel-ram-intake.5175/#post-73425