Time for a new carb. Advice?

[DynaBro]

My 1970 383 (3:91 gearing 4 speed) doesn't have a lot of service history other than oil changes, filters and timing changes. What I do know is around 20K miles ago and the notes say "Complete engine rebuild. Hardened valve seats. Rings. Bearings etc." no mention of cam upgrade. Came with a M1 dual plane intake manifold and Holley Double Pumper 4777-2 with an electric choke. Later added a spacer ( Holley 108-12) for vapor lock.

That carb is toast.

Nearby I have these options on Marketplace:

Edelbrock AVS2 800CFM

Holley 850 Double Pumper #76850BK (probably too big)


I hear the AVS2 is a very good carb for my needs. There are some other options within 50 miles of Hastings, MN on Marketplace like this:

Holley 650 CFM double pumper Carburetor, Carb.

See photos

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but those two seemed the best. Thoughts?

 

[RemCharger]

Best bet in my books is a 3310 VS or a 4779 DP Holley. Both in the 750 range.

 

[496 polara]

Anything in the 650-750 range with a vacuum secondary should perform well. Not aware of an avs in 700cfm.I would double check the part number. I like double pumpers personally but with a 383 automatic and assuming no more than a 3.55 gear I would opt for a vacuum secondary if it were mine.

 

[DynaBro]

Anything in the 650-750 range with a vacuum secondary should perform well. Not aware of an avs in 700cfm.I would double check the part number. I like double pumpers personally but with a 383 automatic and assuming no more than a 3.55 gear I would opt for a vacuum secondary if it were mine.

You are correct! The owner has it listed incorrectly. It has to be a 800 as the box says 1912.

 

[DynaBro]

Anything in the 650-750 range with a vacuum secondary should perform well. Not aware of an avs in 700cfm.I would double check the part number. I like double pumpers personally but with a 383 automatic and assuming no more than a 3.55 gear I would opt for a vacuum secondary if it were mine.

No it is a 4 speed with an A31 package 3:91 gearing.

 

[Darter6]

Edelbrock AVS2 800CFM

It may be a bit much on the street. A AVS2 650 may be a better choice.

 

[DynaBro]

Think I make a mistake saving $30 buying on Amazon rather than Edelbrock direct? Seller is "the Edelbrock Store" but only has 30 day instead of 90 day return.

 

[RJRENTON]

My 1970 383 (3:91 gearing 4 speed) doesn't have a lot of service history other than oil changes, filters and timing changes. What I do know is around 20K miles ago and the notes say "Complete engine rebuild. Hardened valve seats. Rings. Bearings etc." no mention of cam upgrade. Came with a M1 dual plane intake manifold and Holley Double Pumper 4777-2 with an electric choke. Later added a spacer ( Holley 108-12) for vapor lock.

That carb is toast.

Nearby I have these options on Marketplace:

Edelbrock AVS2 800CFM

Holley 850 Double Pumper #76850BK (probably too big)


I hear the AVS2 is a very good carb for my needs. There are some other options within 50 miles of Hastings, MN on Marketplace like this:

http://[URL][URL]https://www.facebo...wse_serp:dbb801b3-07d9-4f38-9053-116683b42dd4

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but those two seemed the best. Thoughts?

Both carbs you noted are too big for your set up. Stay in the 650 cfm range....my preference is rebuild your original. Second choice replacement!, professionally rebuilt carb of same brand and type as original or do it yourself.....remember bigger is not better.....do not succumb to the some advertisements or some uneducated suggestions......who said what and why.......just my opinion.....
BOB RENTON

 

[DynaBro]

Are counterfeit AVS2 a thing? I am seeing wildly cheaper prices on eBay.

 

[Some Car Guy]

You might just find a counterfeit.

As somebody that has actually ran several carbs on a 383, a 3310 750 will work like magic. There I said it. So will a factory 750 avs. I’m sure the avs2 in 800 will be fine.

Only mopar guys hand wring about carb size. Running tiny straw like heads and are paralyzed at the thought they will lose throttle response. Meanwhile in chebbyland, they slap a 750 on a 350 and not even bat an eye. But yeah, a 3310 will rip from off idle to redline.

 

[DeltaV]

There is our Vendor Forum...


Woodruff Carburetor Specialties

 

[Geoff 2]

Edel AVS 2. But which one, 650 or 800? The 650 would be my choice, buuuuuuuuuuuut:
you have a 4 speed, 3.91 axle & a dual plane intake all of which lend themselves to a slightly larger carb. Your call.

 

[DynaBro]

I'm just going to go with the AVS2 650 and see if there's a Black Friday deal. I don't want to jack with this old Holley anymore. I spent all my time and care rebuilding it and this is how it treats me. It can go into the trash. I've had enough.

 

[Dave6T4]

The Edelbrock AVS2 is basically a repop of the Thermoquad. Chrysler used these on everything from 318 to 440, so they are pretty forgiving. The secondary air valve responds to however much air the engine can pump, dependant on displacement.

 

[DeltaV]

I'm just going to go with the AVS2 650 and see if there's a Black Friday deal. I don't want to jack with this old Holley anymore. I spent all my time and care rebuilding it and this is how it treats me. It can go into the trash. I've had enough.

Someone might buy it for parts.

 

[DynaBro]

The Edelbrock AVS2 is basically a repop of the Thermoquad. Chrysler used these on everything from 318 to 440, so they are pretty forgiving. The secondary air valve responds to however much air the engine can pump, dependant on displacement.

I love these interesting factoids.

 

[Jonas Nordstrom]

The repop of the Thermoquad is the Holley Street Demon 625/750. Awesome carbs.
The 650 AVS2 has smaller primaries than the 800 and will give you a snappier response down low.
(If you want that with that gearing?)

 

[DynaBro]

Not super picky. All I want right now is my car back together, running, and not leaking any fluids. What I understand is the AVS2 is a less complicated and very reliable carb that will function well with my build. Basically a Goldilocks option. It is also priced lower than the Holley options. I don't plan to do any racing but I do plan to drive often so simplicity and reliability is key. I just want to rip around the backroads of rural Wisconsin. I don't really comprehend what the actual noticeable performance difference would be between the 650 and an 800 in my daily usage. Seems like pushing for the 800 would potentially run into issues, however small, that I'm not keen on right now for whatever potential benefits the larger CFM offers.

 

[gtxrt]

Not super picky. All I want right now is my car back together, running, and not leaking any fluids. What I understand is the AVS2 is a less complicated and very reliable carb that will function well with my build. Basically a Goldilocks option. It is also priced lower than the Holley options. I don't plan to do any racing but I do plan to drive often so simplicity and reliability is key. I just want to rip around the backroads of rural Wisconsin. I don't really comprehend what the actual noticeable performance difference would be between the 650 and an 800 in my daily usage. Seems like pushing for the 800 would potentially run into issues, however small, that I'm not keen on right now for whatever potential benefits the larger CFM offers.

running 2 800 avs2 on both 440 engines. 1 on a RT and 1 on a Newport. they are a lot better than the 750 AVS for low end power and throttle responses. the 800 cfm will start making more power over the 650 cfm after about 4500 rpms. you need to know what rpm range you like to run.

 

[DynaBro]

running 2 800 avs2 on both 440 engines. 1 on a RT and 1 on a Newport. they are a lot better than the 750 AVS for low end power and throttle responses. the 800 cfm will start making more power over the 650 cfm after about 4500 rpms. you need to know what rpm range you like to run.

4500rpms is kissing the red line so as a non-race driver why would I opt for a carb with features that don't even come into play until there? Honest question. Seems pointless for my driving needs, no?