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#83470 12/08/14 03:34 PM
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this post is pretty much a continuation of my intake manifold post in swap meet.I don`t know much about carburation, having used constant flow fuel injection for the last 20 years or so on methanol. I`m sure that this has been covered more than once but can`t seem to find any posts. I`m going to build a multi carb intake manifold trying to soften the restrictions inherent with a downdraft carb on the inline configuration. need to know what your carb recommendations are

sparks #83472 12/08/14 06:16 PM
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sparks,
There are any number of sites that will help you select the proper size carb, such as the Holley carb site.
In general you will need the displacement of the engine and the approximate volumetric efficiency at max RPM. The vol eff will probably be around 80%, depending on port and cam limitations.
For an engine in the 250 - 300 ci range that number will probably come out around 350 - 450 cfm @ 1.5 in. hg.
That is a good starting point at least. You can try bigger until you start to get driveability issues.Good luck.


FORD 300 inline six - THE BEST KEPT SECRET IN DRAG RACING!
sparks #83473 12/08/14 06:32 PM
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soften the restrictions inherent with a downdraft carb

Such as?

sparks #83474 12/08/14 07:13 PM
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90 degree turn at the base. another 90 towards the head flange on the front and back cylinders and another 90 to the valves. there is quite a difference between the end plugs and the middle ones so I`m going to raise carb base to allow only one soft radius to the head ports with a bigger plenum under the carbs instead of crippling the motor by opening up the gap on the rockers on 3&4

sparks #83501 12/10/14 11:22 PM
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Posting pics of your manifold or ideas (drawing pics) would help us understand better @ what you are looking @ or talking about.

MBHD


12 port SDS EFI
sparks #83505 12/11/14 06:00 PM
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The pes single 4 manifold looks like what I have in mind. Does anyone have any input about it?

sparks #83506 12/11/14 10:39 PM
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This one?

http://www.12bolt.com/250292_products/intake_manifolds

Ask Tlowe how it runs.


You want to use this on the street?

MBHD


12 port SDS EFI
sparks #83510 12/12/14 09:07 AM
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Just had a guy dyno a 292 last week for a vintage class stock car. They made 300+HP and 345 tq all under 5K rpm.
I am going g to be testing one this spring on our 41 Hudson.


Inliner Member 1716
65 Chevelle Wagon and 41 Hudson Pickup
Information and parts www.12bolt.com

sparks #83564 12/14/14 07:03 PM
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mean buzzin, no drag race only. There is a picture of my car on the ha/gr forum under advice and opinion.


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