What is the total cfm rating of the 340-6? - Moparts Forums

Register Log In Moparts Forums Moparts Question and Answer What is the total cfm rating of the 340-6?

Print Thread

What is the total cfm rating of the 340-6? #385000 07/24/09 11:10 AM 07/24/09 11:10 AM
Joined: Jan 2003 Posts: 1,619 MA R ragtop OP top fuel
ragtop OP top fuel R Joined: Jan 2003 Posts: 1,619 MA	If this is different from the 440-6, then why? Thanks.

Re: What is the total cfm rating of the 340-6? [Re: ragtop] #385001 07/24/09 11:23 AM 07/24/09 11:23 AM
Joined: Feb 2003 Posts: 12,675 Columbia, CT M moper I Live Here
moper I Live Here M Joined: Feb 2003 Posts: 12,675 Columbia, CT	No... advertised dry flow numbers are 350 on center, 500ea on outboards for 1350cfm. Wet flowed they are closer to 980cm (the more true rating) Small blocks have differences in calibrations, like air bleeds and metering blocks, jets, etc IIRC. But basically same same. Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.

Re: What is the total cfm rating of the 340-6? [Re: ragtop] #385002 07/24/09 11:24 AM 07/24/09 11:24 AM
Joined: Jul 2008 Posts: 224 Kentucky E ewolfe enthusiast
ewolfe enthusiast E Joined: Jul 2008 Posts: 224 Kentucky	Total cfm rating is 1300cfm. 500cfm for the center and 350cfm for each outboard. I'm wrestling with my combo right now...5" of vacuum at idle and 6 a/f screws...makes for a fun tuning experience.

Re: What is the total cfm rating of the 340-6? [Re: moper] #385003 07/24/09 06:39 PM 07/24/09 06:39 PM
Joined: Jan 2003 Posts: 31,036 Oregon A AndyF I Win
AndyF I Win A Joined: Jan 2003 Posts: 31,036 Oregon	1350 is the rating when using the 2bbl system. That isn't the same rating system as used for 4bbl carbs so you can't compare it to a Holley 4bbl. I think you divide by the sq root of 2 to get the standard rating.

Re: What is the total cfm rating of the 340-6? [Re: AndyF] #385004 07/24/09 06:52 PM 07/24/09 06:52 PM
Joined: Feb 2005 Posts: 4,314 Prospect, PA BSB67 master
BSB67 master Joined: Feb 2005 Posts: 4,314 Prospect, PA	Quote: 1350 is the rating when using the 2bbl system. That isn't the same rating system as used for 4bbl carbs so you can't compare it to a Holley 4bbl. I think you divide by the sq root of 2 to get the standard rating. Correct

Re: What is the total cfm rating of the 340-6? [Re: BSB67] #385005 07/24/09 11:34 PM 07/24/09 11:34 PM
Joined: Jan 2003 Posts: 931 D dulcich super stock
dulcich super stock D Joined: Jan 2003 Posts: 931	I think it is square root of new pressure drop divided by old pressure drop, to arrive at the flow at the new pressure drop. Can't really make sense of the formula you guys are discussing above. -dulcich

Re: What is the total cfm rating of the 340-6? [Re: dulcich] #385006 07/24/09 11:47 PM 07/24/09 11:47 PM
Joined: Jun 2004 Posts: 893 Tustin, CA P pishta super stock
pishta super stock P Joined: Jun 2004 Posts: 893 Tustin, CA	In Vizards book, he estimated the max pull through the six pack from a stock 340 equated to about 780 CFM. 440 would be more, but to say the six pack flows 1350 would be correct only in a motor that could pull that. NASCAR 390's flow gobs more than 390 at 9200 RPM, but they are all flowed at a certain benchmark pressure/vacuum. 12 Grand Caravan 06 T&C 02 T&C 96 Breeze 65 Barracuda "S"

Re: What is the total cfm rating of the 340-6? [Re: dulcich] #385007 07/25/09 01:33 AM 07/25/09 01:33 AM
Joined: Jan 2003 Posts: 31,036 Oregon A AndyF I Win
AndyF I Win A Joined: Jan 2003 Posts: 31,036 Oregon	Same difference Steve, just a different way to say it. 2bbl carbs are rated at double the pressure drop for 4bbl carbs so you use the sq root of 2 to compare the flow ratings. 1350 cfm in 2bbl rating is roughly the same as a 950 cfm 4bbl. 1350 x .707 = 950

Re: What is the total cfm rating of the 340-6? [Re: AndyF] #385008 07/25/09 08:56 AM 07/25/09 08:56 AM
Joined: Jan 2003 Posts: 9,982 Ansonia, CT C CJK440 master
CJK440 master C Joined: Jan 2003 Posts: 9,982 Ansonia, CT	Quote: Same difference Steve, just a different way to say it. 2bbl carbs are rated at double the pressure drop for 4bbl carbs so you use the sq root of 2 to compare the flow ratings. 1350 cfm in 2bbl rating is roughly the same as a 950 cfm 4bbl. 1350 x .707 = 950 Well if 2 bbls are rated at twice the pressure drop of 4 barrels which have double the barrels, shouldn't a 6 pack be rated at even lower pressure drop? Something like 712 cfm?? 2017 Contusion Blue Challenger T/A 392 M6 "BLKNBLU"

Re: What is the total cfm rating of the 340-6? [Re: CJK440] #385009 07/25/09 04:09 PM 07/25/09 04:09 PM
Joined: Apr 2007 Posts: 1,261 ILL mark7171 pro stock
mark7171 pro stock Joined: Apr 2007 Posts: 1,261 ILL	yes

Moderated by Al_Alguire, Hotwheelsjr, moparts, not_a_charger, RangerDan440, tboomer

Hop To

Powered by UBB.threads™ PHP Forum Software 7.7.1