Profrom Carb...
Thread Starter
Le Mans Master
Joined: Nov 2004
Posts: 6,434
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St. Jude Donor '07
Profrom Carb...
If i order the profrom race card do i need mech cfm or vac cfm? The link is here http://www.proformparts.com/v2/catalog/carburetors.html Its kind off a stupid question but you guys say its stupidier not to ask so im asking. Also what cfm do you think i need . Im building a 350 with around 10.5 to 1 pistons and 58 cc heads i dont what the cam is yet though. Tell me about other things that could make the cfm different.
Last edited by yellow73sb; Dec 4, 2004 at 09:55 PM.
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
its hard to imagine you need mechanical secondaries, CFM is a measurement of the airflow, mech vs vacuum refers to how the secondaries open... most people who race use mechanical secondaries, i hate to generalize but i would guess a vacuum secondary would work fine for you...its also what i'm using...
Senior Member since 1492
Joined: Aug 2000
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From: Just because I'm paranoid doesn't mean people aren't out to get me...
St. Jude Donor '09
An old time rule of thumb is 1.6 x the amt of HP you're producing. 400 x 1.6 =640 cfm. My guess 650-750 Holley DP. For street use, get the vac sec.
On Rats you can go larger, they like to breathe.
On Rats you can go larger, they like to breathe.
Team Owner
Joined: Jul 2001
Posts: 182,997
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From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Originally Posted by Jughead
An old time rule of thumb is 1.6 x the amt of HP you're producing. 400 x 1.6 =640 cfm. My guess 650-750 Holley DP. For street use, get the vac sec.
On Rats you can go larger, they like to breathe.
On Rats you can go larger, they like to breathe.
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