Cutting hole in hood?

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Crazy4408pac

Crazy4408pac

N. Michigan
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Looking for some pix, of how the openings were finished. Also any re-bracing.
Just about ready to cut an opening,in my 72 Dart's hood. So, looking for ideas as how to finish the cut edges.
Weld in a piece around it? Should I put in some bracing? I'd hate to see it fold in half. Also, how much extra space for engine torque?

Thanks for any help.
 
What kind of hood scoop?

The holes for the factory scoops weren't finished at all, they were just 4-1/8" diameter holes that were drilled in. The factory put a set of rubber seals on them that are raised a bit to keep water from running in, that was it.

Link to a set of seals...

http://www.ebay.com/itm/DMT-MOPAR-70-74-A-Body-Fresh-Air-Hood-Scoop-Seals-Dart-Demon-Duster-/360907368449

Snorkel scoop

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dual scoops

attachment.php
 
Not sure what kind of hole you plan to cut, but here's pics and description of what I did for a blower:

http://www.70duster440.com/hood.html

It's all tied to the inner structure and isn't flimsy at all. I did retain the 'light' hinge springs I used with a glass hood before and they hold it up. Engine flex will be determined by the motor mounts you're using. You shouldn't need a ton of clearance - even with old rubber biscuit mounts.
 
I hope you can see it in this photo.The hole was re-braced with angle.
 

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72bluNblu said:
What kind of hood scoop?

The holes for the factory scoops weren't finished at all, they were just 4-1/8" diameter holes that were drilled in. The factory put a set of rubber seals on them that are raised a bit to keep water from running in, that was it.

Link to a set of seals...

http://www.ebay.com/itm/DMT-MOPAR-70-74-A-Body-Fresh-Air-Hood-Scoop-Seals-Dart-Demon-Duster-/360907368449

Snorkel scoop

attachment.php


dual scoops

attachment.php
Click to expand...


This post should be a "STICKY" if it's not already. :thumrigh:
 
Crazy4408pac said:
.............. So, looking for ideas as how to finish the cut edges. ..............
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Measure 3 times, cut once.

Finishing the hole, what I did was deburr the hole then slit some small plastic tube and used silicone to hold it around the hole.
 
I didn't care about factory correct on my car.
 

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Locomotion said:
This post should be a "STICKY" if it's not already. :thumrigh:
Click to expand...

I'm sure it is, I linked it from another FABO thread somewhere. It's not my picture...

moparmarks said:
I didn't care about factory correct on my car.
Click to expand...

Did you seal the scoop to the hood? Otherwise water will get under the edges of the hood scoop and run right in. That's why the factory used the gaskets, the gasket sticks up over a 1/4" from the surface of the hood on the top side. Keeps water from running across the hood and into the engine compartment.
 
I didn't use a gasket. I plan on driving this car and will probably get caught in the rain so water will come through the openings. The plan is to use a 70-2 B Air Grabber air cleaner setup.
Yep was the original matching hood. Yep quite rare indeed. Probably have 3 or 4 of them down in the yard.
 
You didn't mention anything about using a scoop, so I'm guessing you're possibly running a tunnel ram or supercharger that will stick through the hood. There are so many different ways to go about finishing the edges of a hole you cut in your hood. The amount of bracing you'll need depends on the size of the hole relative to the particular hood.

When we decided to cut a hole in our '68 Charger hood we were very careful. We first removed the hood hinges and latch so we could LIFT the hood off. With the engine (and the blower) in the car we took measurements to approximate where the hole needed to be.

Our first cuts were conservative. - Nothing worse than hacking a hole that's too big that will require filling later. After our initial cuts we tried fitting the hood and noted wherever we needed additional trimming. Eventually (after subsequent cutting) the hood finally cleared enough to close.

You're not done cutting yet. As the hood opens & closes it moves forward & back. The next step was to remove the blower and re-attache the hinges. Once we properly aligned the hood on the car, we re-installed the blower.

With everything assembled we knew we couldn't close the hood anymore without additional trimming. As we lowered the hood we marked where we were hitting. A few more cuts and we were in pretty good shape but we had to cut a little extra to allow for linkage travel, blower belt tension adjustment, and the motor rocking. When we were done the hood opened & closed without any clearance issues.

What to do with that hole???

Our hood was noticeably flimsy after we'd made the opening. To strengthen it we chose to make filler pieces between the outer sheet metal and the inner structure. After welding the pieces in place the hood was almost as sturdy as before we'd made the hole.

I'd read a build article where the guys welded 5/16" brake line to the top of the hood around the perimeter of the hole. It allowed for a better finished opening that strengthens the hood and provides sort of a 'drip lip' so that less water will run into the opening. That's the next mod we did. When we were done, the hood was actually sturdier than it had been before we cut the hole.

Naturally, you'll have to use filler to cover the tubing.

View attachment 1.jpg

View attachment 2.jpg

View attachment 3.jpg
 
This Dual quad filter, will stick through the hood by an an inch and a quarter. So, I'm thinking an inch clearance around it. Too much? Will be cutting the opening the same shape as the filter.
 

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Crazy4408pac said:
This Dual quad filter, will stick through the hood by an an inch and a quarter. So, I'm thinking an inch clearance around it. Too much? Will be cutting the opening the same shape as the filter.
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I would think that if you're going to chain the motor or put some other form of movement limiter on it you'd be OK. The higher the position of the intake/carbs/air cleaner, the farther it will move. Without some form of limiting engine movement you'll probably still be OK, but I think I'd test it before totally finishing the hood. - No sense in marring the body work.

Make sure the hood doesn't catch on the lid as it opens. We really were surprised at how much we had to cut for the extra clearance as the hood rises, but we're sticking a lot further through.
 
1967 'cuda said:
You didn't mention anything about using a scoop, so I'm guessing you're possibly running a tunnel ram or supercharger that will stick through the hood. There are so many different ways to go about finishing the edges of a hole you cut in your hood. The amount of bracing you'll need depends on the size of the hole relative to the particular hood.

When we decided to cut a hole in our '68 Charger hood we were very careful. We first removed the hood hinges and latch so we could LIFT the hood off. With the engine (and the blower) in the car we took measurements to approximate where the hole needed to be.

Our first cuts were conservative. - Nothing worse than hacking a hole that's too big that will require filling later. After our initial cuts we tried fitting the hood and noted wherever we needed additional trimming. Eventually (after subsequent cutting) the hood finally cleared enough to close.

You're not done cutting yet. As the hood opens & closes it moves forward & back. The next step was to remove the blower and re-attache the hinges. Once we properly aligned the hood on the car, we re-installed the blower.

With everything assembled we knew we couldn't close the hood anymore without additional trimming. As we lowered the hood we marked where we were hitting. A few more cuts and we were in pretty good shape but we had to cut a little extra to allow for linkage travel, blower belt tension adjustment, and the motor rocking. When we were done the hood opened & closed without any clearance issues.

What to do with that hole???

Our hood was noticeably flimsy after we'd made the opening. To strengthen it we chose to make filler pieces between the outer sheet metal and the inner structure. After welding the pieces in place the hood was almost as sturdy as before we'd made the hole.

I'd read a build article where the guys welded 5/16" brake line to the top of the hood around the perimeter of the hole. It allowed for a better finished opening that strengthens the hood and provides sort of a 'drip lip' so that less water will run into the opening. That's the next mod we did. When we were done, the hood was actually sturdier than it had been before we cut the hole.

Naturally, you'll have to use filler to cover the tubing.

View attachment 1714853049

View attachment 1714853050

View attachment 1714853051
Click to expand...

Farggin show off. lol
 
There is a storie on the HOTROD MAG.site with a rambler American. On how they measured and cut the hood.
 
Here are a few links to some POWER NATION videos about trimming the hood by tying the inner & outer sheet metal together.

http://powernationtv.com/two-minute-tech/2min-209/how-to-trim-a-hood-for-a-blower-part-1

http://powernationtv.com/two-minute-tech/2min-210/how-to-trim-a-hood-for-a-blower-part-2

I couldn't find a link to the site where they'd welded brake tubing around the opening. You could use larger tubing to make a more pronounced lip but it would be harder to form. The brake line was easy.

There have to be a zillion ways to fab the opening. If you use your imagination you may come up with an idea no one else has tried. The bottom line is to meet whatever criteria you have for the finished project. SNKEBIT has a build thread here on FABO. In it he shows that he's been modifying the inner structure of his Barracuda hood so that it will look factory made from the bottom even with the addition of his scoop.
 
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