Best Carb for a ‘69 383 Road Runner

[Jeremy Nelson]

Hello all,

I have a ‘69 RR (bought this car on Monday) rebuilt, stock 383 HP, original heads, original intake, exhaust manifolds, Original RR cam, A-833 4-speed, 3.55 sure grip.... and, previous over installed a Holley 80457-12, single-feed 600 cfm, vac. Secondaries, Electric choke. I’m not sure why they did this but with all I’ve read and how the car runs, I feel the carb is well undersized even with the stock 383. To add to this, it absolutely will not idle until she warms to about 150 degrees. I’ve not tuned it much yet, but wanted to get some opinions about what I should be using here? Thinking for looking for an original AVS, or moving to something in the 750 cfm range...would this be too much? Should I be using a carb with mech. Secondaries given the 4-speed and gear set? Electric choke? I feel like this car should idle very well even cold and above that, it should scream and it just feels sluggish to me... maybe the secondaries are just not opening...any help is much appreciated.

 

[PP1RT]

Is the choke hooked up and getting 12v keyed power? Are you pumping the accelerator before starting to engage the choke?

 

[Jeremy Nelson]

I am, and yes the choke has 12V power.

 

[Jeremy Nelson]

*keyed 12V power

 

[PP1RT]

Is the choke closing when you do that?

 

[Jeremy Nelson]

I’m not certain on that but I will check. Would you say a 600 would be undersized? What about Vac secondaries?

 

[PP1RT]

Should be ok for everything but all out racing. Vacuum secondaries definately better on a street car. Make sure the choke blades are closing all the way on a cold start.

 

[Jeremy Nelson]

Thank you very much for your time and detail. I appreciate it!

 

[moparedtn]

It should be noted here that the Holley 3310 750cfm vacuum secondary carburetor was actually used part of the time on the 383 RoadRunners by Plymouth right from the factory. It remains one of the easiest to tune/runs good out of the box carburetors you can fetch for a stock Mopar big block to this day.

 

[62MAX]

Don't want to start a war but you are going to have to show "real" documentation.The only factory installation of the 3310 that I am aware of was on the 396 375 horse Chevelle.

 

[WileE]

Never seen a 3310 on a factory Mopar.

 

[rumblefish360]

I agree. It was a 4160 Holley 600 cfm carb from the factory. Though a 750 would help wake it up, the 600 is fine since that is what the factory gave it. And since the engine is stock.....

It’s not the cubes but the power it puts out and the intended purpose of the engine in whatever weight car. Many factors involved.

 

[rlem1977]

Chrysler used only the Holley model 4160 carb. The 3310 was originally part of the model 4150 carbs. In the '70s Holley changed the 3310 to a 4160 model. I do not believe Chrysler used the 3310.
http://www.hotrod.com/articles/mopp-0111-chrysler-oem-carburetors/
http://www.rodauthority.com/tech-stories/fuel-cooling/historic-holley-carburetor-milestones/

As to the OPs concerns: I believe the 600 cfm you have is too small for the 383. Vacuum secondaries are fine. I'd recommend an electric choke. Either Holley #0-80508 or #0-80459. I am not a Carter/Edelbrock fan, I find Holley's easier to tune and work on. That's just my preference. Others on this site can give a better perspective on C/E tuning. Good luck, have fun.

 

[Photon440]

Even if it reached 100% volumetric efficiency, a 383 won't use more than 600 cfm until after 5500 rpm.

 

[PP1RT]

Chrysler used only the Holley model 4160 carb. The 3310 was originally part of the model 4150 carbs. In the '70s Holley changed the 3310 to a 4160 model. I do not believe Chrysler used the 3310.
http://www.hotrod.com/articles/mopp-0111-chrysler-oem-carburetors/
http://www.rodauthority.com/tech-stories/fuel-cooling/historic-holley-carburetor-milestones/

As to the OPs concerns: I believe the 600 cfm you have is too small for the 383. Vacuum secondaries are fine. I'd recommend an electric choke. Either Holley #0-80508 or #0-80459. I am not a Carter/Edelbrock fan, I find Holley's easier to tune and work on. That's just my preference. Others on this site can give a better perspective on C/E tuning. Good luck, have fun.

600 cfm from the factory was adequate until modifications were made and he already has the electric choke on it.

 

[Xp29h]

I will say before I pulled the low compression 383 out of my charger, I had taken the Holley 650 off it and placed a Holley 3310 750cfm vac secondaries and electric choke on it. After that, th engine ran the best it could. I didn’t run it long that was but a definite improvement. The 3ngine was not built correctly and had some issues, like low CR, pistons rings way too tight no clearances and poor low deck height.

Good luck..

 

[moparedtn]

I stand corrected. It was the 4160 Mopar used on the 383 A/T cars in '69.
Other manufacturers used the 3310 on some of their stuff and I actually learned how to work on one on my '69 SS Chevelle 396.
I also do know that the great Ehrenberg first told me to try one on a 440 I was running in a '68 Super Bee back in the early 80's
and he was, as always, right - the thing worked beautifully right out of the box.
Mia culpa. My apologies.

 

[moparwacko]

In a pure stock application, I would recommend an 1806 Edelbrock. It's a Thunder series, 650 cfm, electric choke.
It will be hard to beat out of the box, and use their phenolic spacer if you plan on running pump gas.
I believe the original AVS was 625 cfm?
The more you modify, the more I would recommend a Holley.
My 2 cents

 

[66Satellite47]

I believe that a carb that's a little too small is better than too big. Having said that, in the early '70's I replaced the stock 2bbl setup on my 383 with a DP4B Edelbrock manifold & a 3310-1 (780) Holley. It ran GREAT. Also it all depends on which style carb you are most comfortable working with, the Carter/Edelbrock or the Holley. I got very used to the Holley's, but had an aftermarket Carter AFB that worked really good for several years on the street. Never had any luck bringing back to life any of the AVS's I tried. A 600 -750 of either Holley or Carter style will work fine with the 383. Good luck.

 

[rlem1977]

Even if it reached 100% volumetric efficiency, a 383 won't use more than 600 cfm until after 5500 rpm.

That is true using the cfm calculators available on various sites. Here is an example though...had a GM 350 c.i. / 290 hp crate engine, GM recommended a 670 Holley, I decided a 600 was good enough. Engine ran okay, never great. Switched to the GM recommendation and that thing woke up.