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Discussion Starter #1
I have a 4" cowl hood on my bbf powered fox body with a holley 750 dp and weiand stealth intake. Clearance between the carb and hood is minimal and I use no air cleaner as the car is track only.

A machine shop tech told a buddy of mine that the clearance issue is costing significant power loss and that I could pick up 2 tenths or more with additional clearance. The concept makes sense, but I'm surprised the benefit would be that great. Anyone have any thoughts on the matter before I spring for another hood (or cut this one up)?
 

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WOuld make a difference with a hood scoop but not with a cowl. I have had both on my car and now I have the smallest cowl on my car I could put. Times are still the same.
 

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Discussion Starter #4
WOuld make a difference with a hood scoop but not with a cowl. I have had both on my car and now I have the smallest cowl on my car I could put. Times are still the same.
So I guess a 5-6 in cowl makes no sense then. I'm gonna start looking around for scoops even tho I prefer the cowl look more.
 

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I know a guy who raced without an air clearner once (ME!!). I had a valve cover stud come out and fly down the carbuerator when I was 4/5's of the way down the track. It made a tremendously hiddeous noise. I thought I just broke the motor. When I disassembled the motor I found the valve cover stud pounded into my nice soft aluminium head by the #4 piston. It also scared the cylinder so bad that it had to be sleeved. That was VERY EXPENSIVE!! ....take my advice. Don't race without an air cleaner. It just isn't worth it. I hope you learn from my own (dumb) experience. Did I mention that was EXPENSIVE??

:eek:
 

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Discussion Starter #7
Maybe it's not such a bad thing to have so little hood clearance!

In all seriousness, I may have already gotten my warning from the Air Cleaner Gods. In one of the rare occasions last season where I was actually going rounds in a bracket race I developed a bad miss and had to bail in the qtr finals. Started pulling plugs and turns out the plug in the #1 cyl was closed shut. Could very well been a foreign object sucked in and spit out.
 

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We fault this for a few years. WE run a 65 Mustang with a 3 1/2 cowl hood (tube frame car). There is about 4 inches from the carb to the bottom of the hood. It would lay down about 2/3rd down track and just do nothing. We tried all kinds of trays sealing to the hood, completely open under the hood, even tried to ram air it from the front of the hood. Finaly we seen a picture of the car at speed and it looked like the hood was pushed down, so we put a stand from the carb to the hood and that fixed the problem! Oh and we run no air cleaner. 4 inches is enough for us, but anything less and it just lays down.
 

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Discussion Starter #11
Appreciate the info guys. Sounds like there may be something to this. My best so far is an 11.20, so an 11.0 would be nice with nothing but a hood swap.
 

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We fault this for a few years. WE run a 65 Mustang with a 3 1/2 cowl hood (tube frame car). There is about 4 inches from the carb to the bottom of the hood. It would lay down about 2/3rd down track and just do nothing. We tried all kinds of trays sealing to the hood, completely open under the hood, even tried to ram air it from the front of the hood. Finaly we seen a picture of the car at speed and it looked like the hood was pushed down, so we put a stand from the carb to the hood and that fixed the problem! Oh and we run no air cleaner. 4 inches is enough for us, but anything less and it just lays down.
Gotta love them track photographers! lol
Rob
 

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1st... don't space the K-Member to get more hood clearance. Keep in mind you need proper driveline geometry and that don't help! You need a taller hood!

2nd... If this is a track use only car then you need to have a pan built that seels around the carb and only allows air from the cowl to be used. Otherwise you get turbulent air and hot air up through the engine bay... and if the carb is close to the hood then it doesn't get "clean" air.

Hope that helps!
 

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Actually if it is a strip only car you don't want to run a screen, but have a good plug for it when you are transporting it or anytime your not making a run! Like our Hood Scoop plug... it goes right back in at the top end and comes out right before I start it.
 

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Discussion Starter #17
Great advice and much appreciated. I will definitely be looking into the scoop/plug setup.
 

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I tend to disagree with Cale here. For the few exta thousandth's a screen would slow you down it is worth the extra insurance to keep the motor safe. If you are like me and don't have sponsors helping to build your motors and you have to pay for them yourself I think you are crazy to run without one.

Cale is right here however.. If you run all out and just want the best time possible regardless of price then no screen is the way to go.


...did I mention that was EXPENSIVE!! :D
 

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That is 2 demerits for disagreeing with me!! LOL! :p
 

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Cale forgets that we don't all pit on the pavement, and that the tracks only clean up once a year (when the pro's are there). I will never run my car again without some type of air filter after seeing the difference. A-B-A testing. :)

When I get my pro stock ride, I'll let the motor builder decide.
 
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