Slant 6 4bbl Carb Selection

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You don't have to worry about the secondaries on the 750 Edelbrock. They will never open because there would not be enough air flow in a sorta stock engine. The primaries are no bigger the then a 350 Holley or for that matter an Autolite 21xx which are good carburetors. So it should work.

Dutra ran a 750 Edelbrock on his 210" green toad car. This was a 12 second car on nitrous. It also had a corresponding fuel system capable of fueling the system. This included a Dutra HyperPac, a set of his cast iron exhaust manifolds and 110 gph mechanical fuel pump.
 
Sigh.
When will the BS stop???????
[1] 750 Edel secs will never open. Yes they will, they are a mech sec carbs. The secs go to WOT when the primaries go to WOT. The sec vel valves may not move, but there is a lot of air leakage around them that could lean the mixture.
[2] Prim are no bigger than a 350 Holley. Yes they are: Edel Pri 1 11/16", Holley 1 1/2"
 
Bewy said:
Sigh.
When will the BS stop???????
[1] 750 Edel secs will never open. Yes they will, they are a mech sec carbs. The secs go to WOT when the primaries go to WOT. The sec vel valves may not move, but there is a lot of air leakage around them that could lean the mixture.
[2] Prim are no bigger than a 350 Holley. Yes they are: Edel Pri 1 11/16", Holley 1 1/2"
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It will never stop. Get used to it.
 
Might need a more powerful toilet flush, to flush away the BS......
 
Bewy said:
Running a 750 cfm carb of any brand on a slant 6 that will be street driven is a baaad idea. The large primary barrels will nit be conducive to good throttle response. There is a reason why manufacturers select carb size commensurate with the engine size [ & at greater cost ] , rather than a one size fits all.
SpriceyStuff said:
Hey guys. I want to do a performance slant six build, and I originally wanted to do a triple Weber setup. Since I don’t have the cash and Redline hasn’t been able to resume manufacture of the manifold, I’ve decided to cut my losses and just go for the cheaper 4bbl route. I’ve found a manifold that’s in stock, but I want some recommendations for what carb to put on it. I’ve bought a bigger cam, and I’m
SpriceyStuff said:
Hey guys. I want to do a performance slant six build, and I originally wanted to do a triple Weber setup. Since I don’t have the cash and Redline hasn’t been able to resume manufacture of the manifold, I’ve decided to cut my losses and just go for the cheaper 4bbl route. I’ve found a manifold that’s in stock, but I want some recommendations for what carb to put on it. I’ve bought a bigger cam, and I’m planning a set of 3-2-1 headers for the exhaust. How many cfm can I make use of? I don’t wanna blast all my cash away on a bigger carb than I can actually use, but I also don’t wanna miss out on any gains by going smaller than I can. What do you guys think?

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planning a set of 3-2-1 headers for the exhaust. How many cfm can I make use of? I don’t wanna blast all my cash away on a bigger carb than I can actually use, but I also don’t wanna miss out on any gains by going smaller than I can. What do you guys think?
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SpriceyStuff said:
Hey guys. I want to do a performance slant six build, and I originally wanted to do a triple Weber setup. Since I don’t have the cash and Redline hasn’t been able to resume manufacture of the manifold, I’ve decided to cut my losses and just go for the cheaper 4bbl route. I’ve found a manifold that’s in stock, but I want some recommendations for what carb to put on it. I’ve bought a bigger cam, and I’m planning a set of 3-2-1 headers for the exhaust. How many cfm can I make use of? I don’t wanna blast all my cash away on a bigger carb than I can actually use, but I also don’t wanna miss out on any gains by going smaller than I can. What do you guys think?

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If you use the AussieSpeed intake, it has no heat to aid atomization and vaporization of the fuel. A carburetor with annular boosters has better signal and they do a better job of atomizing the fuel than standard boosters. The Edelbrock AVS2 carbs have annular primary boosters. If your intended use is primarily a snappy street engine, I would go with a 500 CFM 1901 with electric choke.
You can put the annular boosters into Performer Series carbs. Edelbrock tech suggests starting with the equivalent AVS2 calibration. That appears richer, but remember that todays pumo fuels contain 10% to 15% ethanol, which requires richer "jetting" to maintain the proper A/F ratio. Edelbrock does not sell the boosters separately. If you get a Performer 500 or 600, contact Dan at The Carburetor Shop in Minnesota. A new cover gasket will be supplied with the boosters. Also purchase a calibration kit for the equivalent AVS2 carburetor.
IMHO, unless racing only, the 1407 is too much for a street slant. Either keep it for a built a bit 360 ir sell it and use the money towards a 1901 Edelbrock.
Regarding the headers, don't you mean 6 into 2 into 1? I would seriously consider headers that provide ground clearance for a street driven vehicle. The low hanging tubes can get flattened real quick on speed bumps and such. Exit stage left any advantage they may have provided.
 
Dale Davies said:
IMHO, unless racing only, the 1407 is too much for a street slant. Either keep it for a built a bit 360 ir sell it and use the money towards a 1901 Edelbrock.
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This is kinda what I was getting from others too. Thanks for all the info! I’ll definitely look into the 1901 and the boosters.
 
SpriceyStuff said:
This is kinda what I was getting from others too. Thanks for all the info! I’ll definitely look into the 1901 and the boosters.
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If you purchase a 1901, it will come with the annular boosters.
The boosters are to upgrade a performer carb.
I am confident that you will be happy with the 1901 should you go that way. I would get a calibration kit to tune it. One good thing about a carb is that it is not a maintainance part like brakes, tires and spark plugs.
 
JEGS bought by a Chinese "firm". I would avoid at all cost now. Likely start unloading reverse engineered crap that may be "inexpensive" up front but will come back to bite your buns down the road.
It is like purchasing clothing from Wally World. Take socks, in 3 months the heels have holes. Why would that be? They are made from recycled Yak turds! I do not trust underwear "made in china" either. After the children's toys painted with lead base paints, I do not trust what could be in the dyes used. Do you want something sketchy in close proximity to your privates? Not me!
Do I want sketchy quality parts in my car at 60 MPH or when it is -35° outside? Not if I can help it! I would rather pay more up front and have a bit more peace of mind. At 70 years I have to look after all the pieces I have left.
 
Where is the Chinese link? All the contact names for Greenbriar are Anglo-Saxon.
 
Bewy said:
Where is the Chinese link? All the contact names for Greenbriar are Anglo-Saxon.
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That was my point in posting that link. However, just like everyone else, many if not most of the parts being sold by Jegs, are at least partially sourced from China. There is no way around that. The only thing we can hope for is just like in the late '70's and '80's stuff coming for Japan was garbage. The Japanese kept improving the quality of their product, until it was "world class".
OK' lets get back on track.
 
Dale Davies said:
If you purchase a 1901, it will come with the annular boosters.
The boosters are to upgrade a performer carb.
I am confident that you will be happy with the 1901 should you go that way. I would get a calibration kit to tune it. One good thing about a carb is that it is not a maintainance part like brakes, tires and spark plugs.
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Follow up question: is there a baseline tune that I can start with? Something like “bottom out the screw then turn it back so many turns out” kind of thing that will get it running without having to fuss with it? I’m not planning on putting anything on the engine until I can take it all apart and rebuild it and put it all back together with hot rod stuff, including the cam. Since I’ll be breaking in my cam I don’t wanna have to sit there and turn it over again and again without it starting and building oil pressure.
 
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Dave999 said:
I did the 4bbl thing on a hemi 6
wasn't as good as i'd hoped and ended up paying twice and now have webers

can't say any of these have stock other than they currently seem to have stock


MANIFOLD VALIANT SLANT 6 take 3 x DCOE WEBER - Redline

Chrysler 225 Slant 6 Triple 45 DCOE Weber Kit Weber Performance Carburettors

Redline Performance Intake Manifold - 12-52
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This is what I originally wanted, but no one has the manifold in stock or will any time soon. I have been in contact with a guy in a warehouse in Australia and he was in contact with the manufacturer who said they broke their mold and have been since unable to resume production.
 
SpriceyStuff said:
This is what I originally wanted, but no one has the manifold in stock or will any time soon. I have been in contact with a guy in a warehouse in Australia and he was in contact with the manufacturer who said they broke their mold and have been since unable to resume production.
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Bro, as someone who spent multiple years in the motorcycle world, trust me when I say you do not want a multiple carburetor set up. You will need to buy tools(no big deal) and learn how to properly use them(big deal) to get the carbs synced. Once you have the knowledge and tools it can be fun, but until then it can be one big exercise in futility.

I’d buy the Avs2 and the tuning kit and just run it out of the box. Once you master tuning a Carter/Edelbrock carb, then I would look into adding another carb.
 
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yeah i'll admit the webers are hard work... most of the issues however are float level and ignition. its a 6, its an inherently smooth running engine, so the float level can be 1-2mm higher. the low standard setting is for wobbly vibration prone 4 cylinder motors.
You don't need the rubber mounting. card gasket, direct bolt down..... just saved you months of messing with that advice :)

you buy them configured with a "best guess" for your combo
it doesn't work well enough.... it never does.. flat spots and popping

and instead of balancing the carbs, adjusting timing and getting a decent ignition system, and a minor tweak to idle mixture you fiddle about with the jets and air correctors and venturis for a few years

eventually you end up back where you started with the carb calibration, but only once you get the ignition and curve sorted... and suddenly all is well with the world.



Triple SU

nearly as good: 3 X SU- HS6 would do the job UK ebay, see what you find. new ones cost a fortune but those off 3500 cc rover are reasonable cost second hand
being close to a british car specialist would pay dividends if you choose this route

TRIPLE 1 3/4" SU SLANT 6

less top end with SU but they are great carbs.... japanese dash-pot style carbs are also good


Dave
 
SpriceyStuff is a nubie at this stuff. He doesn't need the complications, or expense, of multiuple carbs. Lets follow the "KISS" theory.
Keep
It
Simple
Stupid
 
well fair enough... :)
I was in the same position.... owned a hurricane manifold, no longer own one, for me at least 4 bbl wasn't that simple.

I moved to simple by buying an inlet manifold and carbs that worked on the standard motor and now i use the same carbs and inlet on a motor with 12.5:1 CR headers and silly cam

depends what you are building for, Drag race or street. I built for torque, tyre smoke and chasing BMWs and Audis, rather than max HP at 6000 + rpm

I found it very easy to define "performance" as my original aim, but not truly understand what i had done until after i had spent $600 on a massive 4bbl inlet.

Dave
 
Charrlie_S said:
SpriceyStuff is a nubie at this stuff. He doesn't need the complications, or expense, of multiuple carbs. Lets follow the "KISS" theory.
Keep
It
Simple
Stupid
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I tried. I gave up.
 
SpriceyStuff said:
Follow up question: is there a baseline tune that I can start with? Something like “bottom out the screw then turn it back so many turns out” kind of thing that will get it running without having to fuss with it? I’m not planning on putting anything on the engine until I can take it all apart and rebuild it and put it all back together with hot rod stuff, including the cam. Since I’ll be breaking in my cam I don’t wanna have to sit there and turn it over again and again without it starting and building oil pressure.
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Generally bottom the idle adjustment mixture screws lightly and then back each out 1 1/2 turns.
To set initial timing, rotate the engine in the direction of normal rotation to #1 at say 5° to 8° BTDC, on compression. Install the distributor with the rotor pointing at the #1 plug wire position. With the cap off and the key in the run position and a circuit test light connected to the negative coil terminal, rotate the distributor housing in the direction the rotor turns when running so the light goes out. Then slowly turn the housing back to advance the timing until the light just comes on. Snug the lock bolt down.
Now the idle mixture and timing are close enough the engine should start right up and run well enough to run the cam in. You should be able to adjust the idle speed screw to maintain 2,000RPM.
After the cam is broken in you can set the idle speed down to specs. Idle mixture can be tweeked and the timing set with a timing light. You may then need to go back and adjust the idle mixture screws again.
 
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for what it's worth, if it's primarily a street motor with a mild cam, you may want to even look at the Aussiespeed 2bbl manifold that has a 2300 holley bolt pattern. might work better and give you more efficiency for the street. another consideration would be since a new AVS is $500, for a street driven vehicle, especially since the aussiespeed manifold doesn't have provisions for manifold heat, it might be worth at least looking at the Holley Sniper or similar EFI systems. just food for thought....eventually I'd like to build up my slanty with some head porting and milling, perhaps deck the block to get compression in the 9:1 range, a cam with about [email protected] duration max (likely one of of the two smallest hughes whiplash cams), clifford shorties, and the 2bbl hurricane running either a holley sniper system, or maybe even trying to do MPFI utilizing a late 90's early 2000's truck throttle body (since I have a complete 318 magnum intake sitting on my garage shelf)....
 
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