carburetor question

[mike mal]

how much cfm is the standard 1969 383 roadrunner rated ????????

 

[ACME A12]

I've heard both 625 and 630 CFM...anybody have some kind of listing for the 4615 or 4616...?

Not that 5 CFM is really going to matter...

 

[Big John]

I had also heard 625 cfm for the 383 and 750 cfm for the 440 version.

 

[mcmopar]

Yeah - something like that - but that was a Carter rating which I have heard was different from Holley's rating as one source I read had said. This source (it's been a long time ago and I can't remember the source - it could have been Chrysler Power Magazine) stated that the real cfm ratings were more like 500 cfm for the 383 and 650 or so for the 440. Have to take that with a grain of salt, though.

 

[Big John]

I just did a search and came up with this:

http://www.mymopar.com/forums/index.php?showtopic=11113

 

[ACME A12]

630 CFM listed for the AVS in that first link. Knew I had seen or heard that somewhere before...but I don't think that was it...

They don't even mention a Holley on a 383 on any of those listings...which obviously is incorrect...

 

[moparchris]

As far as the carbs being rated differently Carter to Holley is true. Carter flows their carbs at 5" of vacuum and Holley flows their 4 Barrels at 3". This makes a 630 Carter a 500 CFM Holley equivalent. Holley 2 barrels (six packs included) are flowed at 5" so they are really something like 930 CFM versus the advertised 1350 CFM.

 

[SomeCarGuy]

Unless it is an all OEM resot, just run a 750. Not an Edelbrock 1407 750. An AVS or a Holley 750. Run a stock AVS and then swap on a bigger carb and you will see why. :drive:

 

[mcmopar]

As far as the carbs being rated differently Carter to Holley is true. Carter flows their carbs at 5" of vacuum and Holley flows their 4 Barrels at 3". This makes a 630 Carter a 500 CFM Holley equivalent. Holley 2 barrels (six packs included) are flowed at 5" so they are really something like 930 CFM versus the advertised 1350 CFM.

Thanks Chris - I was hoping I wasn't way off base.