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what size carb #816309 09/27/10 09:38 PM 09/27/10 09:38 PM
Joined: Feb 2007 Posts: 231 Cumberland County, NJ coronetkid OP enthusiast
coronetkid OP enthusiast Joined: Feb 2007 Posts: 231 Cumberland County, NJ	408 sbc victor jr. intake dart pro 1 heads intake runner 200cc exhaust runner 75cc comb chamber 72cc cam solid flat tappet .244/.252 duration .520/.540 lift SRP flat top pistons comp ratio 10.5 1 3/4 hedman long tubes into x-pipe what do you guys think?

Re: what size carb [Re: coronetkid] #816310 09/27/10 09:45 PM 09/27/10 09:45 PM
Joined: Jan 2003 Posts: 42,714 Spokane Washington ScottSmith_Harms Mr Wizzard
ScottSmith_Harms Mr Wizzard Joined: Jan 2003 Posts: 42,714 Spokane Washington	Holley 950

Re: what size carb [Re: ScottSmith_Harms] #816311 09/28/10 05:25 PM 09/28/10 05:25 PM
Joined: Feb 2007 Posts: 231 Cumberland County, NJ coronetkid OP enthusiast
coronetkid OP enthusiast Joined: Feb 2007 Posts: 231 Cumberland County, NJ	that big? really?

Re: what size carb [Re: ScottSmith_Harms] #816312 09/28/10 08:16 PM 09/28/10 08:16 PM
Joined: Mar 2005 Posts: 3,145 Central NC gch master
gch master Joined: Mar 2005 Posts: 3,145 Central NC	Gearing,stall,weight,etc would help for a race effort.Anything from a 750dp on up will work. An 850 would probably take care of any street/strip effort.

Re: what size carb [Re: gch] #816313 09/28/10 08:25 PM 09/28/10 08:25 PM
Joined: Dec 2009 Posts: 580 PA Moparzrule mopar
Moparzrule mopar Joined: Dec 2009 Posts: 580 PA	MOE had an article on big carbs/small cubes. http://editions.amospublishing.com/MPRE/default.aspx?d=20100701 My Own Personal Adrenaline Rush

Re: what size carb [Re: ScottSmith_Harms] #816314 09/28/10 08:51 PM 09/28/10 08:51 PM
Joined: Feb 2005 Posts: 4,316 Prospect, PA BSB67 master
BSB67 master Joined: Feb 2005 Posts: 4,316 Prospect, PA	Quote: Holley 950 Its not 950 cfm. It has 1.375 venturi like a 750, with contoured body and 1.75 throttle bore. Throttle response of a 750, performance of an 850. Perfect for what you've got.

Re: what size carb [Re: BSB67] #816315 09/28/10 10:12 PM 09/28/10 10:12 PM
Joined: Aug 2003 Posts: 259 Morris County NJ R Rustydog enthusiast
Rustydog enthusiast R Joined: Aug 2003 Posts: 259 Morris County NJ	General rule of thumb, (Cubic inches X Max RPM) / 3456 = CFM

Re: what size carb [Re: Rustydog] #816316 09/28/10 10:16 PM 09/28/10 10:16 PM
Joined: Aug 2003 Posts: 259 Morris County NJ R Rustydog enthusiast
Rustydog enthusiast R Joined: Aug 2003 Posts: 259 Morris County NJ	I'd recommend 750 cfm mechanical secondaries jets 72 & 82 Don't over carburate with an 850 cfm

Re: what size carb [Re: Rustydog] #816317 09/29/10 12:53 AM 09/29/10 12:53 AM
Joined: Apr 2005 Posts: 12,271 Overpriced Housing Central RobX4406 I Live Here
RobX4406 I Live Here Joined: Apr 2005 Posts: 12,271 Overpriced Housing Central	Holley 950hp That formula is only good if you want to under carb an engine IMO. Essenstially, it's good to arrive at the smallest carb you might want to use.

Re: what size carb [Re: RobX4406] #816318 09/29/10 07:56 AM 09/29/10 07:56 AM
Joined: Mar 2008 Posts: 390 kentucky S superbyrd enthusiast
superbyrd enthusiast S Joined: Mar 2008 Posts: 390 kentucky	i would agree on the 750 mechanical. the worst thing most people do is over carburate.....

Re: what size carb [Re: superbyrd] #816319 09/29/10 11:41 AM 09/29/10 11:41 AM
Joined: Apr 2005 Posts: 12,271 Overpriced Housing Central RobX4406 I Live Here
RobX4406 I Live Here Joined: Apr 2005 Posts: 12,271 Overpriced Housing Central	360 at 6500 says 688cfm using the formula. Why is it that many go much faster with larger carbs and have used 1050 dominators doing so. My 360 is getting a 1050 so I must be crazy. That formula is set up for a 1.5" pressure drop, IIRC. I don't know many that think a 1.5" drop is acceptable for a performance engine at full throttle. What adjustments have to be made to the formula for a 1", .5" or zero pressure drop? Something like a 23% increase going from 1.5" to 1.0" comes to mind.

Re: what size carb [Re: RobX4406] #816320 09/29/10 02:17 PM 09/29/10 02:17 PM
Joined: May 2005 Posts: 598 NC, USA D davenc mopar
davenc mopar D Joined: May 2005 Posts: 598 NC, USA	A 750CFM carb will only flow around 640CFM at 1.1" (if I did my math right). At 0.75", it will only flow 520CFM. As I understand it, the issue with lower pressure drops is getting good fuel metering. Getting the carb right under such conditions is why some carb vendors can charge a premium. If that 360 was spinning at 6500RPM, then a 800CFM carb at 1.1" would just meet its needs (assuming 100% VE at that RPM).

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