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Discussion Starter · #1 ·
I have a 67 Firebird with a 73 400ci engine, slight cam, Performer intake, HEI, and quadrajet 4MC carb. I want to add the Ram Air I kit and was told it would mess up performance instead of help it. From reading some posts it looks like the Ram Air kit is simply adding cold air to the carb and not really changing the air / fuel mixture. I am thinking the guy that told me it wouldn't work really didn't know but I may be wrong. Anyone done one of these or knows for sure.
 

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Anytime a engine can breath cool fresh air instead of underhood stale hot air performance is increased, although the percentage is low, it`s a power gain none the less. It`s been said that "ram air" can alter the air fuel mixture, since the vehicle picks up speed and under full throttle, the air comes in faster than the engine can ingest it, I don`t know if this is true or not, it makes sense in the theory, but sometimes theory compared to real world things aren`t even in the same ball park, if you believe it would alter the air fuel ratio, then I would simply drill some relieveing ducts on the back of the ram air scoops to bleed off the excessive air.
 

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The general rule is that you get a 1% power increase for every 10 degrees lower the air temperature you carb is sucking through it.

The fuel mixture does change, you are supposed to richen it a little bit for the ram air.
 

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The way that it was explained to me is that the Ram Air as used on the early Firebirds and GTO's was not very efficient as the system sealed your air intake to the factory hood and scoop which did not have a large enough opening to increase performance, however it also does not hurt the performance either, if you will read the specs on the 67 HO 400's and the Ram Air Version, they are exactly the same. I would say that if you have the pan and foam to convert you bird to ram air, go for it as it looks very good when you open the hood, I am going to add it to my 67 GTO whenever I have the time to build it. Plus did you know that the ram air did not come from the factory back then but was shipped in the trunk and installed by the dealer.
 

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Ram Air

That's one of the things the Firebird on some models was famous for-- Ram Air. You can still get the Factory Ram Air IV from Year One but it's expensive , but as the factory made it, it is a controllable system.
Like Double Vision said you may need some type of bleed off set -up. Is this one your looking at the Air Cleaner Housing type with 2 ducts? Constant Ram Air? Or does it come with a cable type set up were you can open the intake ducts? Just wondering if this is a factory set up.
 

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Discussion Starter · #7 ·
The Ram Air I system that goes on the 67 Firebird is one that uses the two hood scoops and an air cleaner the fits tight into a cut out pan underneath the hood. Supposedly all the air that enters the hood scoops is pushed down through the air cleaner which is sealed to the hood and then through the carb. The down side is if it is raining. They say you have to put some foam in the scoops to keep out the water, not sure what happens with no air coming in. I guess I will have to figure that one out. Any ideas? Probably block the scoops and take off the pan seal so it can breath under the hood.
 
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