383 CARB recommendations.

[747mopar]

The simple thuth is: "You pay your money and tske your choice". Vintage carbs are like fine wine.....they get more expensive with time....but like fine wine perform remarkably well. There was an old addage: "fancy gizmo's don't work" (aftermarket fuel injection) or work after spending tons of money and time and frustration to make them do what's advertised.
I am a classic car person who strives to make my efforts appear original....using OEM parts when possible. The old vintage Carter carbs are available on the internet or eBay. Sometimes at reasonable prices.....most vendors know what they are offering....some carb "experts" have no clue as to their correctness.....or search for carbs offered as cores....these are excellent sources of the small parts removed by these self proclaimed experts.
It is truely amazing how many persons have no clue how a carb functions yet trust strangers and their often misguided reasons or opinions and will spend $$$$, based on what they hope to achieve. DO YOUR OWN DUE DILIGENCE .... do not just go by hearsay. Again, this is just my opinion.
Bob Renton

I can agree with a lot of that but with a few exceptions like aftermarket EFI. I still haven't pulled the trigger after seeing so many installs go south but it seems the time has come, Holley appears to have nailed it with every install I see gaining praise. It doesn't matter where a person's allegiance lies(carb/EFI) you cannot deny the benefits of EFI where a computer along with sensors can keep the mixture spot on in all conditions.

The second is the "fine wine", most of these old carbs are heavily neglected meaning corrosion, wear and abuse... overtorquing, crazy mods, etc. If your an OE guy than by all means fix one up but if you want a carb that will just do a great job then new is a better more trouble free route IMO.

I've rebuilt Quadrajets, Motorcrafts, Mikuni's, Holleys, Demons, Carters and now run a QF which by the way cost less than an off the shelf carb even after having it custom spec'd... I like starting out with one that's free of all the years of added headaches. Having said that I really like carbs mostly because it's part of owning a classic, wrenches and screwdrivers not computers.

 

[91r/t]

I can agree with a lot of that but with a few exceptions like aftermarket EFI. I still haven't pulled the trigger after seeing so many installs go south but it seems the time has come, Holley appears to have nailed it with every install I see gaining praise. It doesn't matter where a person's allegiance lies(carb/EFI) you cannot deny the benefits of EFI where a computer along with sensors can keep the mixture spot on in all conditions.

The second is the "fine wine", most of these old carbs are heavily neglected meaning corrosion, wear and abuse... overtorquing, crazy mods, etc. If your an OE guy than by all means fix one up but if you want a carb that will just do a great job then new is a better more trouble free route IMO.

I've rebuilt Quadrajets, Motorcrafts, Mikuni's, Holleys, Demons, Carters and now run a QF which by the way cost less than an off the shelf carb even after having it custom spec'd... I like starting out with one that's free of all the years of added headaches. Having said that I really like carbs mostly because it's part of owning a classic, wrenches and screwdrivers not computers.

Amen brother. I'm with you 100%. I don't want to spend my days chasing a small vacuum leak due to a worn shaft or anything like that. Old carbs are beat and most were neglected. Most carbs I see sitting on shelves aren't exactly boxed and clean. They are usually covered in **** and crusty. Hell, walk through Carlisle and look at all the carbs for sale there and tell me how many are clean looking and aren't worn. Most need major rebuilds. I am all for it on an original car, but that's about the only place I will say a Carter AVS belongs on in my book.

 

[RJRENTON]

747Mopar,
Thanks for your opinion. I too have rebuilt/tuned/modified all the carbs you mentioned. IMHO the Rochester Q-Jet (and those manufactured by Carter under license) were superb in design, especially the triple stacked primary booster ventirii and the secondary acceleration fuel system (acting like an accelerator pump system but operating on differential pressure). The only down fall was the lack of availability of components (primary jets and metering rods and secondary metering rods and rod hangers) but this could be over come by trips to the junk yard.....almost all parts interchanged across the different models that were supplied by GM. The QJet was rated at 750 CFM and 800 CFM.
AND TO THE ORIGINAL person who made the first question about which carb to use on a 383 engine....I have an original Holley R4668 model 4160 from a 1971 Dodge charger with an "N" engine callout. It is rated at 750 CFM @ 3" pressure drop, 1-9/16" primary x 1-3/4" secondary throttle bores. It has the backward idle system, down leg secondary boosters, vacuum operated secondaries, and a hot idle compensator (bimetal valve) circuit. The car had ORIGINAL A/C.
If interested PM me to discuss particulars.
Bob Renton

 

[68Moparmaniac]

Agree with you there.....too much carb can make it run like crap for sure. The 750 just seems like it is well suited for a mild to decent 383 from my experience. My fathers almost stock 383 in his charger has a 600cfm single feed on it and it seems lathargic at times like it wants more for sure. The recommendation of a mechanical secondary carb on an automatic makes me question whoever he was talking to at Holley.

If you look back at the 340 6 barrel which has a cfm rating of 1200 and runs like a stripped ape. It's all about the components matching up and working together to utilize that amount of flow. So if your heads, manifold and exhaust are designed to handle the extra flow efficiently then in this case more IS better....IMO

 

[72golddustermike]

Went with brawler 770. RUNS GREAT

 

[91r/t]

Went with brawler 770. RUNS GREAT

Awesome man! Glad it worked out for ya! Fine tune that baby and you'll be happy for years.

 

[RJRENTON]

68moparmaniac,
I believe that the 340 six barrel (and also the 440 six barrel engine) set up was (is) rated at :
End carbs = 500 CFM @ 3" pressure drop
Middle carb = 355 CFM @ 3" pressure drop
Total CFM = 1355 CFM
The secret of why it works so well is coordinated components and insuring that mixture velocity is in the 40-50 ft/second range.
A lot of the after market fuel injection systems use, i believe use a throttle body type injectors and all of the associated electronic measuring components: MAP, TPS, TEMP, O2, crankshaft position sensors (timing) snd perhaps air flow volumetric measurement as density expressed as grams/second.
But for a classic car nothing beats a good old carb. This is just my opinion of course.
Bob Renton

 

[68Moparmaniac]

68moparmaniac,
I believe that the 340 six barrel (and also the 440 six barrel engine) set up was (is) rated at :
End carbs = 500 CFM @ 3" pressure drop
Middle carb = 355 CFM @ 3" pressure drop
Total CFM = 1355 CFM
The secret of why it works so well is coordinated components and insuring that mixture velocity is in the 40-50 ft/second range.
A lot of the after market fuel injection systems use, i believe use a throttle body type injectors and all of the associated electronic measuring components: MAP, TPS, TEMP, O2, crankshaft position sensors (timing) snd perhaps air flow volumetric measurement as density expressed as grams/second.
But for a classic car nothing beats a good old carb. This is just my opinion of course.
Bob Renton

You are absolutely correct, I was thinking of the factory 2x4 set up (1250cfm).
The six pack did have more flow than the 2x4's.