intake question
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Senior User
Joined: Mar 2004
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From: Rocky Point, North Carol
intake question
I know this has probably been asked before, but I am about to go with a 4bbl on my 150, and I have checked around a little, but I wanted to see what you guys thought of this combo:
Weiand action+ dual plane intake
Road Demon 725cfm carb
I'm running a 76' 400, stock cam and ignition.
I was afraid that the 725 might be a little much for the motor with the stock cam, but the specs show it for 350-500 motors with stock to moderate cams. (Jegs) The truck is a hunting/trail truck. I'm not looking to run it at the bogs or anything. Should I stick with the 625? Also, the weiand intake is non-EGR, but the motor is EGR.
Weiand action+ dual plane intake
Road Demon 725cfm carb
I'm running a 76' 400, stock cam and ignition.
I was afraid that the 725 might be a little much for the motor with the stock cam, but the specs show it for 350-500 motors with stock to moderate cams. (Jegs) The truck is a hunting/trail truck. I'm not looking to run it at the bogs or anything. Should I stick with the 625? Also, the weiand intake is non-EGR, but the motor is EGR.
Cargo Master
Joined: May 2003
Posts: 2,561
Likes: 1
From: Earth
Too much carb if you ask me, your stock 2v is about half that (I believe they are somewhere around the 350cfm area......give or take). I'm only running an Edelbrock 600 CFM with the Ford SVO cam, headers, about 9.75:1 compression, bored .040, full MSD ignition, and with the Weiand intake that you want. This is on a '71 400 out of an LTD that is in my '53. I had to get the tuning kit for the carb and richen it up though because out of the box it was too lean. 
There are quite a few guys on here that are running 600 cfm carbs on mildly hopped up engines. A 750 is just wasting way too much fuel on a stock engine, and even some modded engines.
Here's your basic formula for calculating proper (ball-park) cfm rating for your carburetor:
(Engine Displacement (in cubic inches) X Maximum RPM) / 3,456
So, for my 400 it is.............(410*5000)/3456= 593 cfm. Again, a rough estimate, and it doesn't hurt to round up to the next biggest size, so my 593 would be 650cfm. However, I am getting good results, so far, with my 600 cfm and messing with the needles and jets.
There are quite a few guys on here that are running 600 cfm carbs on mildly hopped up engines. A 750 is just wasting way too much fuel on a stock engine, and even some modded engines.
Here's your basic formula for calculating proper (ball-park) cfm rating for your carburetor:
(Engine Displacement (in cubic inches) X Maximum RPM) / 3,456
So, for my 400 it is.............(410*5000)/3456= 593 cfm. Again, a rough estimate, and it doesn't hurt to round up to the next biggest size, so my 593 would be 650cfm. However, I am getting good results, so far, with my 600 cfm and messing with the needles and jets.
Last edited by 53fatfndr; Mar 13, 2005 at 10:25 PM.
Thread Starter
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Senior User
Joined: Mar 2004
Posts: 198
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From: Rocky Point, North Carol
thank you very much. I think the 625 would work nicely then. I have heard a lot of good things about the weiands, and I've run the performers before in Chebbies with okay results. Is there one you guys would pick over the weiand in that same general price range?
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From: Okla.
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Elder User
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From: Eastern Pa
I agree 750 is too big. I have a 408 with mid level cam, headers, duals, roller rockers, 8.7:1cr, and run the 1406 edelbrock 600. I had to change the jets and metering rods up a little and it needs the next size up squirters to eliminate the hesitation when you stomp on it. But it will go to 5500 easy without starving.
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Cargo Master
Joined: May 2003
Posts: 2,561
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From: Earth
Originally Posted by tastyklair
I agree 750 is too big. I have a 408 with mid level cam, headers, duals, roller rockers, 8.7:1cr, and run the 1406 edelbrock 600. I had to change the jets and metering rods up a little and it needs the next size up squirters to eliminate the hesitation when you stomp on it. But it will go to 5500 easy without starving.
Hey tastyklair, what size rods and "squirters" are you running? I'm still playing around with mine, but I'm pretty happy with where I'm at now.... I actually forgot what's in there at the moment. However, I'll be fideling around with it next week some, so I'll have to recheck to see what's in there
Postmaster
Joined: Aug 2001
Posts: 4,270
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From: Delaware
I am running a 750 cfm Edelbrock on my highly modified 400(check my gallery). It runs great and has good street manners. The gas mileage isn't very good, but it is a Weekend Warrior, not a daily driver.
Elder User
Joined: Jan 2004
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From: Eastern Pa
I would forget too if I did'nt write it down. I currently have #1449 (.070x.037) rods and #1427 jets (.098). I have changed the step up springs a couple times but then it got too cold to do until spring. The squirters are still original which is why I need to get the larger ones.