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seeking opinion on possible peril with carb
https://www.slantsix.org/forum/viewtopic.php?t=13478		 Page 2 of 2
Author:  Dennis Weaver [ Mon Jun 27, 2005 2:41 pm ]
Post subject:  Re: My love for mopar renders me totally GM carb ignorant so
Quote:
AFB or Edelbrock
Same thing.
Quote:
After y'alls advice, I spent the afternoon today looking at AFB and Edlebrocks and see only 600, 800, 1000 cfm.
There are several here running the 500 (which should be readily available), if you're lucky, you can score a vintage "competition series" Carter in 400cfm (model 9400, I believe). .....or you can locate an OEM AFB like I did for a '65 Dart 273. It flows 400cfm.

D/W
Author:  SlantSixDan [ Mon Jun 27, 2005 3:04 pm ]
Post subject: 
OK, now the next question becomes:

500cfm AFB? Or 650cfm AVS?

440_Magnum...?
Author:  440_Magnum [ Mon Jun 27, 2005 4:23 pm ]
Post subject: 
Quote:
OK, now the next question becomes:

500cfm AFB? Or 650cfm AVS?

Magnum_440...?
Well, I have an OPINION on that... but since I don't currently own anything smaller than a 318 (at least not with a carb) I don't have much data.

My feeling is that both a 500 CFM and a 650 CFM are both a lot of carburetor for a 225 CID long stroke torque motor. Given that both will be operating in the over-carbed zone, I'd go with the AVS even though its bigger. The AVS is a lot more forgiving about oversizing it for an engine, just like a Thermoquad is. Case in point: my 318 never had a truly smooth transition onto the secondaries of a 600 CFM AFB. But when I put a Thermoquad on it (750-800 CFM, depending to whose rating system you believe) it was MUCH smoother because the TQ is an air-valve secondary carb like the AVS and Quadrajet, even though the over-carbing was worse. When I put the AFB on my 383, it was perfectly smooth because it wasn't over-carbed.

My rule of thumbs are 1) err on the side of undersizing a carb, and 2) if you know you're flirting with over-carburetion, use an air-valve secondary Carter, Edelbrock, or Rochester or vacuum secondary if you must go with a Holley.
Author:  Dennis Weaver [ Mon Jun 27, 2005 4:29 pm ]
Post subject: 
Quote:
OK, now the next question becomes:

500cfm AFB? Or 650cfm AVS?

Magnum_440...?
I vote adapt an AVS top on the 500. The new AVS's are overpriced. I think any old OEM AVS top could be modified lightly (the air flap where it needs to clear the booster venturies) to work. I keep saying I'm going to try this, but just haven't gotten around to it yet. The spring-loaded AVS air door is definitely superior to the standard AFB weighted door.

D/W
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