Mad Scientist Testing Carter AVS 4966S (short video)

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dibbons

dibbons

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I found what I believe to be a Carter AVS 4966S carb on the hodgepodge 340 I purchased a few years ago (kind of hard to read the model number see photo). Anyway, did a search on the carb number and found fellow forums members believe it to be 625-630 CFM and came on low-performance 1971 440's. This "nut" in the video believes it to have 750 CFM.



Carter AVS 4966S.JPG
 
4966 is a 625 cfm carb. 625's had 1 7/16" pri bores, 1 11/16" sec bores.
If still on the engine, you can verify by the venturi diam. 625 has 1 3/16", 750 has 1 7/16".
 
I'm actually working on turning a 4966s into a blow through carb as we speak. It has the same venturi and throttle bore size as a 500cfm edelbrock. There is no way it's more than that.
 
Does your 4966 have the same measurements I posted in post #4? If it does, then it is a 625 cfm carb. Those specs come from a Carter catalog.
 
Bewy said:
Does your 4966 have the same measurements I posted in post #4? If it does, then it is a 625 cfm carb. Those specs come from a Carter catalog.
Click to expand...
Yep. Compare the specs to edelbrock. Same as a 500 cfm one. Carter obviously used a higher water column to rate their carbs than standard 1.5". Maybe they used 3".
 
66fs said:
No secondary boosters in a factory AVS.
Click to expand...
That's true, but it does have the spray bar in the way. The edelbrock booster is the same size as the bore diameter too. There's no way that carter flowed 625cfm with the venturi sizes. It was simply carter's odd way of flowing 4bbl. Maybe someone could flow a factory avs and a edelbrock 500avs.
 
So Carter Lied? Frankly Oliver, you don't know what you are talking about. I have a couple of Carter catalogs from the 1970s & they list replacement AVS carbs, models 6433 to 6437, for Chry engines. They have the same dimensions as production AVS carbs & are listed in the catalog as flowing 630 cfm.
Quite believable, as the unobstructed secs will flow a lot of air.
 
Bewy said:
So Carter Lied? Frankly Oliver, you don't know what you are talking about. I have a couple of Carter catalogs from the 1970s & they list replacement AVS carbs, models 6433 to 6437, for Chry engines. They have the same dimensions as production AVS carbs & are listed in the catalog as flowing 630 cfm.
Quite believable, as the unobstructed secs will flow a lot of air.
Click to expand...
Umm. Maybe not lied, but they did not use the industry standard of 20.4" of water column to flow the carbs. The secondaries are not unobstructed as you say. Maybe you are the one who doesn't know what the hell you are talking about. What's funny is instead of having a discussion you spout crap. I've flowed many carbs, carters were the only ones that never matched the claims of carter. Tell me why similar edelbrock carbs always have lower cfm ratings? If I had an edelbrock avs I would do a comparison to the modded 4966s I'm currently working on just so you would be less ignorant.
 
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Neither did BG flow their H clones at 1.5" of Hg like Holley did. I have no idea what Carter flowed their carbs at, but when you look at comparable throttle bore/venturi sizes of other brands, the flow #s are close, if not the same.


As far as Carters not matching cfm claims: the 750 Holley has 1 3/8" pri & sec venturiis, and 1 11/16" pri & sec bores. A 750 Carter AFB has the same bore sizes but considerably larger venturiis: 1 7/16" pri, 1 9/16" sec. The AFB does have a velocity valve in the secs that might have a small impact on flow.
Maybe you need to re-calibrate your bench.

The secondaries of a carter AVS are relatively unobstructed compared to AFBs. AFBs have a venturi that reduces flow & a bulbous booster that reduces flow; the AVS has none of that, straight bores & a brass 1/4" tube sticking out of the bore.

Edel may have 'selected' 600 cfm to compete with the popular H brand. Why don't you ask them?
 
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