Outboard carbs for 6 Barrel

[racinguy25]

I am looking for outboard carburetors for my Superbird 6 Barrel setup. I called Holley and talked to someone and asked if either of these 2 numbers would work, 4365-1 (original number I think) or 4790 and was told there was no difference in the specs so either would work. There is another one #4672 that 'looks' the same, 500 cfm, and I am wondering if any of the 3 would work. They are all listed in the factory rebuilt section and are about half the money for a new one, and after reading their criteria to sell as rebuilt they sound like a good deal. Any comments, other than I'm a cheapskate, on whether all 3 will work, or not?

 

[davek]

I believe the 4790 is for a 340 6 pack I could be wrong.

 

[Daves69]

...........Any comments, other than I'm a cheapskate, on whether all 3 will work, or not?

Lol, one could have marine six pack carbs and make 'em work if they want.

But I do happen to know where a '70 automatic setup is available.

 

[33 IMP]

Unless you have to have date and list number correct for a restored car, ANY vacuum secondary end carbs will "work", even the corvette version. Just a matter of getting the tune right, and there's lots of Sixpack threads here.
(And don't be fooled by that 500cfm, 1350cfm baloney, rated the same as a four barrel they flow about 1000cfm.)

 

[PurpleBeeper]

I'm no expert, but I've run several six-pack setups over the years, big block and small block.
4365-1 = 70/rear (& maybe for an air grabber car? I never knew there was a difference)
4790=corvette number maybe?
4672=71/rear

440 Six Pack Carburetor Identification

How do I tell a back carburetor from a front one? Let's suppose I'm at a swap meet and a vendor has an end carburetor for sale... How do I tell of it's a front or back? Is there an easy to identify a front one vs a back one?

www.forbbodiesonly.com

There may be some internal differences, but they all "fit and work". In general, the differences appear to be only in the metering plates on the outboard carbs & those often get modified....so use what you can find cheap IMO

 

[RJRENTON]

IMO.....A lot depends on wether you want a "numbers matching" installation or not. Since you mentioned a "Superbird" six barrel setup, the car must be a 1970 model. And since you did not specify auto or 4 speed transmission, the major difference is in the center carbs idle, off idle, and transfer system calibration points, possible the accelerator pump's cam setting.
The Holley numbers are: center carb R4375 manual trans, R4376 auto trans 355 CFM; front carb: R4382 front carb, R4383 rear carb either transmission 500 CFM each. The correct carb build date would proceed the build date of the car.
BOB RENTON

 

[racinguy25]

Lol, one could have marine six pack carbs and make 'em work if they want.

But I do happen to know where a '70 automatic setup is available.

Mine is a 4 speed, so passing gear is more fun to get to than an automatic, but thanks.

 

[racinguy25]

I believe the 4790 is for a 340 6 pack I could be wrong.

You are correct, the number matches what is called for, for a 71- 340, but that really doesn't bother me if it works right. This 6 barrel setup has been a problem ever since I got the car and I am trying to get it to run right for a change. You guys bailed me out a year or so ago with advice and I was able to get it going for a while. I'll put the old carbs that came on it in a box for the next guy to worry with.

 

[davek]

the center carb is the main carb if thats carp the 6 pack will never run right. My last set up I bought a new center carb for that reason. Good luck and post some pics of your SuperBird.

 

[33 IMP]

the center carb is the main carb if thats carp the 6 pack will never run right. My last set up I bought a new center carb for that reason. Good luck and post some pics of your SuperBird.

Dave, your comment is a bit fishy.......

 

[racinguy25]

IMO.....A lot depends on wether you want a "numbers matching" installation or not. Since you mentioned a "Superbird" six barrel setup, the car must be a 1970 model. And since you did not specify auto or 4 speed transmission, the major difference is in the center carbs idle, off idle, and transfer system calibration points, possible the accelerator pump's cam setting.
The Holley numbers are: center carb R4375 manual trans, R4376 auto trans 355 CFM; front carb: R4382 front carb, R4383 rear carb either transmission 500 CFM each. The correct carb build date would proceed the build date of the car.
BOB RENTON

Thanks, now I know the right numbers. I just need to open my wallet a little further and order an R4382 and a R4383. These things seem stupid expensive for what you get, just a simple 2 barrel carburetor, no choke. There's that cheapskate thing going again.

 

[davek]

Dave, your comment is a bit fishy.......

I meant if center carb is junk the 6 pack will never run right. We have to spend money sometimes

 

[davek]

just seen it

 

[racinguy25]

the center carb is the main carb if thats carp the 6 pack will never run right. My last set up I bought a new center carb for that reason. Good luck and post some pics of your SuperBird.

Already bought the center carb, it's the one that has been the problem. I rebuilt it and it was better, but still carp, or crap. ;-)

 

[davek]

Already bought the center carb, it's the one that has been the problem. I rebuilt it and it was better, but still carp, or crap. ;-)

Brand new? Are you using the flat paper intake gaskets? I bought the thick ones for heat soak and regret buying them,nothing but problems with them and went back to factory gaskets.

 

[racinguy25]

Thanks for asking for pics 33 IMP.

 

[RJRENTON]

Already bought the center carb, it's the one that has been the problem. I rebuilt it and it was better, but still carp, or crap. ;-)

I believe that Holley is offering an R4140 model for the center carb replacement. This carb is based on a 1971 design that uses a evaporative emission control system for the fuel bowl vent. As best I can remember, I believe this carb used a "backward" idle system, that, as the mixture screws were turned in (clockwise) the idle mixtures got "richer".....the screws were an air bleed adjustment. There were additional changes to the off idle and transfer circuits. Origional carbs are available on the internet or EBay but at mega dollars costs...... Just talking out loud.......
BOB RENTON

 

[racinguy25]

Brand new? Are you using the flat paper intake gaskets? I bought the thick ones for heat soak and regret buying them,nothing but problems with them and went back to factory gaskets.

I will just use the one's that come with the carbs and they are the flat paper ones.

 

[racinguy25]

I believe that Holley is offering an R4140 model for the center carb replacement. This carb is based on a 1971 design that uses a evaporative emission control system for the fuel bowl vent. As best I can remember, I believe this carb used a "backward" idle system, that, as the mixture screws were turned in (clockwise) the idle mixtures got "richer".....the screws were an air bleed adjustment. There were additional changes to the off idle and transfer circuits. Origional carbs are available on the internet or EBay but at mega dollars costs...... Just talking out loud.......
BOB RENTON

The new center one I bought, is a R4144-1. It 'looks' identical to the one on the car and the numbers match, so as soon as I buy the other 2 I will get them in, cross my fingers and hope I have spent enough to fix all my carb problems.

 

[RJRENTON]

The new center one I bought, is a R4144-1. It 'looks' identical to the one on the car and the numbers match, so as soon as I buy the other 2 I will get them in, cross my fingers and hope I have spent enough to fix all my carb problems.

Good luck with your endeavours......very great looking car.....B5 Blue is always a show stopper, plus a Superbird as well....outstanding..... My RS23V0A****** is one of 678 GTXs built with the 6 barrel and is one of 350 built with a 4 speed (A833 18 spline shaft).....and 328 were auto trans. Its an A34 super track pack car, w/ a Dana 60 4.10:1 rear, PS/PDB, max cooling pkg, PS pump oil cooler.