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Does anyone ever make their twin bulge hoods functional?

Righty Tighty

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One of the things that has surprised me the most about the Barracuda as I learn about them, is that the twin bulge hoods aren't functional. They look cool, but they don't do anything to add air flow to the engine compartment. In my opinion, it's useless to have something on a car that is supposed to be performance-oriented, but ends being ONLY for looks (kinda like the faux beadlock wheels on 4x4 trucks).

Here's my question. I'm sure at least one person out there in the world has cut out the scoops on these hoods to make them functional, but 1) is it common practice, and 2) does it hurt the resale price of the hood? I know it's my car and I can do what I want to it, but is it frowned upon when people do this? And I ask about the resale value of the hood, because ultimately I think I'd like to go with an AAR style hood. I just can't afford it at the moment.

As a temporary solution, I'd like to cut out the scoops to increase air flow in the engine compartment, mostly because I live in southern Arizona and summer (and 110+ degree temps) is quickly approaching. I'd love to hear your feedback.


Image borrowed from the web.

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Poolshark314

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There were a couple other threads about doing this, but I think the consensus was that since they weren't designed to be functional, it may actually hinder performance by messing with the airflow and causing turbulence
 

hofilbert

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Keep or sell the OEM hood, and buy a fiberglas AAR or twinbulge repro hood. Dont' chop up something OEM that is only getting harder to find when someone else might be looking for your style hood. Buy a replacement new hood and have at it.
 

Righty Tighty

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There were a couple other threads about doing this, but I think the consensus was that since they weren't designed to be functional, it may actually hinder performance by messing with the airflow and causing turbulence
That’s interesting, thanks for the input. I suppose I could’ve searched the forum for previous threads — hate to be that guy. Well I guess that explains why I don’t see any that have been cut when I do an image search online.
Keep or sell the OEM hood, and buy a fiberglas AAR or twinbulge repro hood. Dont' chop up something OEM that is only getting harder to find when someone else might be looking for your style hood. Buy a replacement new hood and have at it
Thanks. That was another reason I was hesitant to go chopping it up. It’s in great condition, and I’m sure there would be someone eager to have it as-is, so it would be a shame to alter it just for the sake of having a temporary solution. It gets pretty hot here, and with headers/closed hood I’m always watching the temp gauge like a hawk.

I think I’ll save the time and effort, and spare the hood. I thought about going with a shaker hood, but it seems to be pretty difficult to piece meal everything together. The only kits I could find included a lot of what I already have and couldn’t find a shaker bubble by itself.
 

704406

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I had a hood that someone did the modification that you are talking about. I had a hard time selling it, no one wanted a cut up hood. You have gotten great advice from other members, don't cut your stock rally hood.
I have a spare OEM shaker bubble and a 4BBl base plate that I would consider selling if you want to go the shaker route, although with the seal around the adapter ring sealing the hood to the top of the motor I can't see how that will help your cooling issue.
 

Righty Tighty

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You know, that's something I didn't even think about. I've never owned a car with a shaker setup, so I was not clear as to how it worked. I think I will stick with the plan for the AAR hood and leave my OEM hood unmolested.

Can anyone chime in as far as lift-off hoods vs hinged? Is a lift-off hood always a 2 person job?
 

1972CudaV21

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This has been done a thousand times & most ended up as hack jobs. Like others have said, do it to a fiberglass hood & store the original.
 

rklein71

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You know, that's something I didn't even think about. I've never owned a car with a shaker setup, so I was not clear as to how it worked. I think I will stick with the plan for the AAR hood and leave my OEM hood unmolested.

Can anyone chime in as far as lift-off hoods vs hinged? Is a lift-off hood always a 2 person job?
I had a fiberglass shaker hood on a 70 Challenger back in the mid eighties that was held on with hood pins. It was easy to take off by myself... I just grabbed the hood by the hole and lifted it off. Piece of cake, and it wasn't hard to put on either.
 

hofilbert

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Just yesterday, I saw a black AAR hood (functional repro) on FB Marketplace?? maybe, or FB Ebodies. Looked nice and ready to go. I can't find it now.
 

Righty Tighty

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Thanks! Great forum here. I'm going to leave the hood alone and focus on more important things like a soft-shifting transmission..... Best believe you'll be seeing some questions from me in the transmission section! Haha.
 

Cuda416

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In my non engineer head, I think the only way to make them functional, and not from a "ram air" standpoint, would be to open them up, be then somehow open up the back end as well. Think Shelby about a hood with the nacelles. My understanding is most of the openings are to remove heat and pressure from the engine compartment. The rear ones are supposed to "pull" air out and front ones "let" fresh air in.

I could be way off base though.

What is a fact though is that the cuda scoops are too low and unobtrusive to let any air in. The boundary layer would probably make any air skim right over them.
 

Dodgeboy

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The first inch of air on your car is "boundry air" and it is slow moving air. From a performance point opening up the scoops will not add anything. This is why the mopar t/a scoop & 6-pack hood scoop are designed with the bottom of the scoop hole roughly 1 inch above the hood.
 

70chall440

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The reality is that the vast majority of hood scoops and ram air type systems, they don't add a lot in terms of performance unless you are running wide open. About the only thing most of them do is let rain and debris into the engine compartment... Not hating on them as i do like the looks of them but they do not really do a lot much like most of the spoilers on the market.
 

Righty Tighty

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Well, the main goal here wasn't for performance, but rather more for cooling purposes. I haven't owned the car long enough to know how hot it's going to run during the hot summers here, but I do know my Scamp doesn't like temps over 110 or so. Letting rain in isn't much of a concern at all, since we don't get much rain here and I can easily choose to just not drive it in the rain.

I don't dislike the look of the twin bulge, so maybe I'll run it for a summer to see if I even need additional cooling in the first place. Even then, obviously I can find other (and perhaps more effective) ways to cool the engine besides opening up the hood, like radiator and fan options.
 

NoCar340

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The hood is essentially a terrible place to vent to increase cooling (as well as a terrible place for cold-air induction). The only place on it that's any good is near the front, which is a low-pressure area created by air deflected from the grille area. The center is essentially a dead area, as mentioned a few times here, and the rear is a high-pressure area created by the air's interaction with the windshield (that's why your cowl vents are there, and why Chevelles used Cowl Induction).

Rear-facing NACA ducts (like the AAR scoop, but smaller) cut into the hood a few inches behind the radiator support would help, the closer to centered to the radiator the better, but the forward third is the only place on the hood really worth attempting anything. Anyone who's ever owned a second-generation Firebird Trans Am can tell you the fender extractors are very effective, but the closest thing on an E-body is the '71 'Cuda "gills" which A) aren't functional and B) do not have a deflector in front of them to induce a vacuum.

Wrapping or coating your exhaust manifolds or headers will reduce underhood temps, as will blocking the intake manifold's heat crossover if present (and not needed for thermostat function).

As I've discussed elsewhere in another thread, make sure you are using the right thermostat. If it's not all brass & copper construction, and doesn't look like the diagram in the factory decal below, you're handicapping your cooling system. Parts-store thermostats are NFG. You cannot buy the right ones new anymore; the Mr. Gasket Asian copy has an enormous (>70%) failure rate. NOS is your only option, and in your situation I'd definitely be looking for one or more of them.

T-stat Decal.jpg
 

Righty Tighty

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The hood is essentially a terrible place to vent to increase cooling (as well as a terrible place for cold-air induction). The only place on it that's any good is near the front, which is a low-pressure area created by air deflected from the grille area. The center is essentially a dead area, as mentioned a few times here, and the rear is a high-pressure area created by the air's interaction with the windshield (that's why your cowl vents are there, and why Chevelles used Cowl Induction).

Rear-facing NACA ducts (like the AAR scoop, but smaller) cut into the hood a few inches behind the radiator support would help, the closer to centered to the radiator the better, but the forward third is the only place on the hood really worth attempting anything. Anyone who's ever owned a second-generation Firebird Trans Am can tell you the fender extractors are very effective, but the closest thing on an E-body is the '71 'Cuda "gills" which A) aren't functional and B) do not have a deflector in front of them to induce a vacuum.

Wrapping or coating your exhaust manifolds or headers will reduce underhood temps, as will blocking the intake manifold's heat crossover if present (and not needed for thermostat function).

As I've discussed elsewhere in another thread, make sure you are using the right thermostat. If it's not all brass & copper construction, and doesn't look like the diagram in the factory decal below, you're handicapping your cooling system. Parts-store thermostats are NFG. You cannot buy the right ones new anymore; the Mr. Gasket Asian copy has an enormous (>70%) failure rate. NOS is your only option, and in your situation I'd definitely be looking for one or more of them.

View attachment 81827
Thanks for the explanation! Certainly helps me understand the physics of what’s happening to the air as it goes over and around my car. And thanks to others for their info as well. Before now, I hadn’t known about “boundary air” and obviously wasn’t educated on how or why air induction systems worked.

I’ll try to get a stash of thermostats that aren’t NFG (seems the NFG folks put their parts in everyone’s boxes nowadays) so hopefully I can find some new old stock ones - for the Scamp as well.
 

NoCar340

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If you go to mymopar dot com, there are downloadable factory parts manuals available. They're not the most intuitive thing in the world at first, but once you get the hang of 'em they're not bad. Over the years, the numbers changed somewhat frequently (the above-posted one is from a '70s motorhome) but anything through about '73 should be the correct style of thermostat. Obviously, there are different numbers for different temps... keep checking the usual suspects for any/all of the numbers of your chosen temps. In your searches, you will find old-stock aftermarket stats like Robertshaw (the original vendor) and others. If it's all-brass and looks like the above drawing or the photo below, go for it. Robertshaw made them for everyone--except Mr. Gasket, whose stats should be avoided at all costs. I can't stress that enough.

100_3449.JPG



My Valiant drag car has a cheap Asian 3-row aluminum radiator and 10.5:1 W2-headed 340 with a solid roller cam. With the correct style of thermostat it holds 180° with a death grip, even while idling on a humid 95°+ day.
 

Dfr3604cuda

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I've considered this too. I used to drive my Dakota on the most congested road in Pittsburgh. I installed these louvers. The hood was faded, I painted it flat black, it turned out pretty good. The engine temperature dropped considerably.
 
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