Functional Airbox

I would like to make a functional airbox for my hood. What would be the best way to measure the tolerances when the hood is closed? I was thinking of using some low density foam and putting some sort of hardner on the Foam and the closing the hood and letting it cure. then open the hood and the foam would be compressed still to the shape of the tolerances and then i could go from there. Any ideas if this would work or what would be better system to use? any materials that would help?

i was going to do that for a buddy of mine but he said the sensor that was clipped into the stock one wouldnt work the same in the new FG one (sounded like someone gave him a BS story, but whatever) we sorta figgured out a way to do it, but didnt actually get around to doing it but here goes.

We took a white-out bottle and flipped the brush so the bristles were facing up, positioned it where the origional box was and then closed the hood.  we moved it about 4 times getting a rough idea on the hood where the hole should be.  What we were going to do for getting the hight was throwing a lump of playdough on the origional air box and closing the hood, then measure from the intake manifold to the top of the playdough.  From there i could figgure out the rough hight and area of the box. 

To make the box i was thinking of getting a piece of PVC pipe the same size as the mass airflow sensor and  then taping off the manifold area and whatever else so i could lay the base of the box and then i could build up the sides with carboard or whatnot (just to hold the shape while i glassed) then make a lip on the top for a strip of foam around the top of the box so when the hood was closed it would be air tight.  The box would be made to fit a flat rectangle filter that could just sit in the top of the box.  To connect the PVC to the MAS i was thinking of a rubber sleeve connector with clamps.  Its probly not the best way to do it and i might have even changed the way i was doing it halfway through building it, but it was just an idea and thats what i was thinking of if it makes sense.

i dont know what the engine compartment looks like or where your trying to put it, but i am toying with the idea right now of building some engien stuff that has to fit under the hood, so i read this post and then remembered and old practical joke that might be able to work in this instance...    the old joke was that you could freeze shavign cream and after it was frozen, you could cut it out of the metal can and throw the 'shaving cream ice cube' into someones 'locker, car, back pack, etc...' and as it thaws it would expand as normal.

so takign this same idea, take a big garbage bag, and freeze some tripple expanding foam, throw the chunk in the bag, close it off, and put that in the are that you want to get the height of...  it will expand to the top and sides and the bag will stop it from gettign everywhere and it will stop it from trying to mold itself around little things like wires and sensors etc, or getting in places that you would nt need it at.  just my 2 cents of McGuyver moments.

Why freeze it? Couldnt i just spray it into a plastic bag and close the bag? Would the foam melt the bag at all? Last thing i want is some foam all over everything. I Have a Throttle body not a MAF so i was thinking i could mount a mdf box to keep it close and use the foam in a bag to get exact measurements... I like the idea hopefully it wont bust the bag and get everywhere.

here is a picture of my hood

http://www.dakota-durango.com/aftermarket/cervinis1.jpg

heres my engine setup

http://www.dakota-durango.com/aftermarket/fnb48mm.jpg

What kind of hood do you have? I drive the same but a 2k hence the name. Im not sure if i will get it figured out since the guru's on this board arent giving me any real direction must be too busy answering the 1000 posts about speaker rings LOL. Always nice to talk to a fellow RTer. Have you done any other things to your truck?