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Old 07-30-2020, 04:01 PM   #1
gnicholson
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Default Hood to carb clearance

Got a new 532 installed in my 70chevelle. With the 4inch cowl induction hood I have 2 inches of clearance between the hood and the flange of the carburetor. Gen consensus is that 4inches is minimum before airflow robbing turbulence becomes an issue. An aero scoop is prob the best performance wise but even with a lot of surgery to make it smaller they still don't look right on the car in my opinion. They make a Sunoco style cowl induction hood that's raised in the middle and then tapers back towards the windshield. Does anybody have any idea what I should do with this thing
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Old 07-31-2020, 07:19 AM   #2
Hacksaw
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Default Re: Hood to carb clearance

I'd try it like it is. 2" should be ok.
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Old 07-31-2020, 04:04 PM   #3
Tom Goldman
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Default Re: Hood to carb clearance

2" is not enough . .......first thing you will notice is fuel staining on the bottom of the scoop from reversion . ...4" is minimum , more is better to allow the air flow to straighten out and minimize turbulance.
I picked up nearly 2 mph going from 2" to 5 1/2"
Accompanning pics are from a customers car but I did the same thing to a similar scoop for my car .
no one really makes a scoop that is a reasonable length for a Sportsman style car so get out the saw and the resin . ....No big deal to do .
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Old 08-01-2020, 10:28 AM   #4
Lenny5160
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Default Re: Hood to carb clearance

Quote:
Originally Posted by Hacksaw View Post
I'd try it like it is. 2" should be ok.
x2. I’d try it.

Before I started throttle stop racing, I always ran the stock hood which didn’t have near 2” of clearance. I didn’t notice any difference in performance our consistency with the 4” cowl.
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Old 08-05-2020, 05:27 PM   #5
Jim Caughlin
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Default Re: Hood to carb clearance

In SS where stock hood is reqd, there was a test lowering a sheet of plywood over the carb, the height number where performance dropped off was 2" over the stock choke horn.
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Old 08-07-2020, 05:16 PM   #6
gnicholson
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Default Re: Hood to carb clearance

I've decided to glass an aero scoop into the hood. I would post a pic if I knew how to do it
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