How big to make the hole in the hood?

[ragtopfury]

Some of you have seen my low dollar thread on what I'm playing with in regards to my Shelby Dakota. With the carb spacer, the air cleaner needs hood clearance. I am going to cut a hole for the 14 inch cast Edelbrock air cleaner to protrude thru into the space under the twin snorkel scoop that I am adding.
So all that to ask this - How big of a hole? Other than "big enough" of course. How much clearance should I have all the way around it? Is a 16 inch hole plenty big enough to allow for 1 inch of engine movement/flex/vibration all the way around? Motor mounts are original type rubber mounts. The scoop is not yet mounted.

 

[1800MoreMopar]

I would like to guess yet but I havent done this kind of job on my car yet. My actual plan was to mark out where the scoop would sit with pencil or chalk or some other temporary mark on the paint then cut out what you have within the outline (roughly .5-1 inch of clearance all around) and just drive around a block or 2 away in circles with the air cleaner sticking out. If it looks too close then the air cleaner should only contact the hood a couple times before you have a chance to get home and trim more

 

[ragtopfury]

I'm with you on the thought, except my truck isn't mobile yet. I've got plenty to do before she's back on the ground. I'm picking at bits and pieces as time allows. My initial plan is to let the air cleaner stud tell me where the center of the hole will be, drill a 1/4 inch hole there, then draw my circle from that, cut the hole and then position the scoop accordingly front/rear. Hoping to keep it close to the rear edge of the hood.

 

[66340SEDAN]

Remember to center the hole in the hood to the air cleaner....then center the scoop on the hood. Most MoPars the engine is moved to the right more, so if you center the hole in the hood your air cleaner won’t be centered in the hole. On my 1966 Valiant I measured where the air cleaner stud would be, measured how wide I wanted the hole (think I made the hole 16 inches for a 14” air cleaner) Then took a sharpie marker and tied a string to it, (make the string the correct length) the other end of string went to a small punch at the center...pull the string tight and make a circle. I then took an air tool with a cutting wheel and carefully cut it out along the line I made in one nice piece! When done, I painted the lip so there was no raw metal, then took some soft plastic door edge guard trim and stuck it on, looks great! I never ran a hood scoop, so I wanted to make sure I got everything centered nice and a good clean cut since a hood scoop wouldn’t be hiding it.

 

[ragtopfury]

Keith has exactly how I'm doing it. I just marked the bottom side of the hood with the air cleaner stud and just finished drawing a circle with a string. And yes gentlemen and ladies I laid a blanket over top of the engine to catch any metal for my drilling and cutting. It was either that or take the hood back off by myself

 

[ragtopfury]

Looks like I'll be taking a hood back off anyway because I've got to cut some of the under hood bracing. It will be worth it in the end.

 

[64mopar]

Have someone "safely "put it I gear and rev the engine and watch how much movement it has,then cut the hole accordingly.

 

[ragtopfury]

Have someone "safely "put it I gear and rev the engine and watch how much movement it has,then cut the hole accordingly.

I thought about that too except I'm not to the point where I'm ready to fire it up yet.

 

[ragtopfury]

Got the big hole cut. Went 16.5 in diameter. It does pit the scoop at the rear edge of the hood where I wanted it. Still need to cut some of the underbracing out, but the work desk is calling... recess is over for today.

 

[mderoy340]

This is how I setup my 67 dart. Modified a 17" cake pan, thick foam from home depot glued on with 3M door seal adhesive, driver side engine chain with slight slack. After cutting lower bracing installed 10/32 screws to stiffen the edges of the cutout.

 

[ragtopfury]

I've seen the modified cake pan before. I might do the same type of thing. Haven't decided yet. I do like the idea.

 

[j par]

Dual quad situation... I cut a smaller exploratory hole and used 1/4 all tread to make long air cleaner rods then put my air cleaner lids on and traced around them...

 

[ragtopfury]

Here ya go. Once I get the scoop mounted, I'll get a filter that will stick up out of the hole another inch or so.