Hood scoop to big?

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hwy2

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I got this huge hemi scoop. How do I determine hole size. Just cut it huge or close to the edge of cleaner? More forward or to rear?

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What's the purpose of the scoop? Beauty, fresh air, or clearance?
 
In my opinion, yes the scoop is too big.
That said, study the bottom of your hood, open up the area in between the stiffening ribs (you don't have to remove all the space!).
Then plot the bolt locations for hold-down, also to avoid the ribs if possible. That will tell you where to put the scoop.
(But nothing looks stupider to me than a scoop too far forward on a hood.)
 
That's a Texas size hood scoop you got there. If you are really gonna use it cut a small round hole just above the carb. And use a velocity stack with a screen and filter.
 
like all important decisions, you should let the cat decide.

.... it seems as if it's already taken an initial look at it.
 
In my opinion, yes the scoop is too big.
That said, study the bottom of your hood, open up the area in between the stiffening ribs (you don't have to remove all the space!).
Then plot the bolt locations for hold-down, also to avoid the ribs if possible. That will tell you where to put the scoop.
(But nothing looks stupider to me than a scoop too far forward on a hood.)
That’s where all the good air is, right at the front of the hood.
 
Beauty and fresh air. At 318 it was running cool.392 high compression hot. New large 340 radiator cooler nut not cool 195. Not sure of a small hole for pressure. Or a large hole for flow. I don’t want to worry about leaning out and higher speed. Does any of this really matter?
 
I’d turn it around opening facing the windshield as far back as I could. Use a 14” K&N air filter 4” tall with a X stream top and cut the hole in the hood so it sticks through.
 
That scoop is definitely not too big for the car, my hood scoop is the same size Hemi scoop. It has a functional hole in the hood but with the fact you cut thru structural members it has a reinforcement ring added. Hole is about 16” in my hood and I run a 4x14 air filter up thru it. If you would like a few measurements let me know. Additional information is your scoops mounting bolt holes will line up funky on the reinforcement underneath so expect struggles. I did not do this job originally on my hood but did repaint and remount the scoop better this year.

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That scoop is definitely not too big for the car, my hood scoop is the same size Hemi scoop. It has a functional hole in the hood but with the fact you cut thru structural members it has a reinforcement ring added. Hole is about 16” in my hood and I run a 4x14 air filter up thru it. If you would like a few measurements let me know. Additional information is your scoops mounting bolt holes will line up funky on the reinforcement underneath so expect struggles. I did not do this job originally on my hood but did repaint and remount the scoop better this year.

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You did a ring of steel underneath? Yep That is the scoop.i like it better already. Jetting issues?
 
You did a ring of steel underneath? Yep That is the scoop.i like it better already. Jetting issues?

There is a ring of steel welded in that goes thru the hood from bottom of the reinforcement ribs to about 1” above the hood itself and then body filler transition to the hood surface. Yes that filler cracks at that seam and no you can’t see it under the scoop unless you look for it. Hard to see in this picture but I can’t find the ones I thought I had so will have to take a couple new ones. Like I said, I didn’t do original install but cleaned up the install and repainted it all.

Jetting issues I assume you are talking carb and I don’t have any issues with my tune after getting it all dialed (Edelbrock 750 on a 340 with 284/484 cam). I have driven this car on 90 degree summer days and 30 degree winter days on the same carb tune. I am a hair rich for summer and about dead on to hair lean in winter but there’s no jet change for that so it’s just fine lol. Only issue would be getting caught in a rainstorm with fully functioning scoop and no block off methods.
 
There is a high pressure area at the cowl. (Cowl induction) If the scope points backwards it might be better than forwards

If you want some science based info. Get a bunch of pieces of yarn and tape them every few inches apart from the front of the hood to the cowl and from left to right

Then video what they do at various speeds.

The directions they point will indicate high and low pressure areas.

If you put the scoop in a high pressure area and seal the hood around the air filter then more performance.

Unsealed and you could hinder cooling

If you put it in a low pressure area and seal the filter, less performance.

Unsealed and it MIGHT aid cooling.
 
You need a lot of Horse power for a scoop that big. Pushing that through the air is like running into the wind with a piece of plywood strapped to your chest. You must be doing it for looks.

Mopar determined that the Hemi scoop was to big on the hemi cars after 1968 so they were only used for one year. Snorkel and T/A Challenger scoops were the best as per mopar performance chassis manual. six pack second. Your Hemi scoop was determined to be a parachute. Make sure the scoop and hood are fastened down tight.


The restriction of forward movement may not be worth the forced air it provides.
 
That’s not too big….this was a bit hard to see over at night..

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Personally, for the described reasons above by the OP, I'd take approx an inch out of the height of it, and give the car the 67 GTX vibe.

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You need a lot of Horse power for a scoop that big. Pushing that through the air is like running into the wind with a piece of plywood strapped to your chest. You must be doing it for looks.

Mopar determined that the Hemi scoop was to big on the hemi cars after 1968 so they were only used for one year. Snorkel and T/A Challenger scoops were the best as per mopar performance chassis manual. six pack second. Your Hemi scoop was determined to be a parachute. Make sure the scoop and hood are fastened down tight.


The restriction of forward movement may not be worth the forced air it provides.
Interesting to bring in aerodynamics of a particular hood scoop design on a car that is otherwise shaped like a brick LOL. Remember, the very next year after the 1968 Hemi scoop was the introduction of the Dodge Daytona Charger because the grill was catching too much air in Nascar lol. I agree that Mopar did all the R&D to set up these cars to do any type of racing available back in the day, and is invaluable. But for this application looks are more important than speed and it isn’t stealing that much horsepower thru the air to hurt the seat of the pants dyno in my Duster, so it’s perfectly fine. Can everyone please step back and remember everyone has different tastes and the OP asked how to install the Hemi scoop, not should he. His decision to use the scoop was made, now he wants it to function and not fly off. And last I checked Mopar had and installation guide for that too.
 
Interesting to bring in aerodynamics of a particular hood scoop design on a car that is otherwise shaped like a brick LOL. Remember, the very next year after the 1968 Hemi scoop was the introduction of the Dodge Daytona Charger because the grill was catching too much air in Nascar lol. I agree that Mopar did all the R&D to set up these cars to do any type of racing available back in the day, and is invaluable. But for this application looks are more important than speed and it isn’t stealing that much horsepower thru the air to hurt the seat of the pants dyno in my Duster, so it’s perfectly fine. Can everyone please step back and remember everyone has different tastes and the OP asked how to install the Hemi scoop, not should he. His decision to use the scoop was made, now he wants it to function and not fly off. And last I checked Mopar had and installation guide for that too.
Yes that’s what I was getting at. So it won’t take away a measurable difference in seat. I will try to find instructions on the hood. I am putting in hood pins. Thanks everyone. I think I will remove the 1” spacer it’s pretty close if not up against hood now when fully shut. There is a witness mark where bolt for air cleaner top goes. I’m still not clear on if mounting in the front or back or whatever I think looks better.
 
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