.... what do they say about this in the newer rule books?

I can not get anybody to give me a answer. That they will stand behind. But here is a pics of a friends car that runs GT/AA.

General Regulation

7:4 FIREWALL
Each car in competition must be equipped with a minimum .032-
inch aluminum or .024-inch steel firewall, extending from side to
side of the body and from the top of the engine compartment’s
upper seal (hood, cowl, or deck) to the bottom of the floor and/or
bellypan. Firewall must provide a bulkhead between the engine
and/or fuel tank and driver compartment. All holes in firewall must
be sealed with aluminum or steel. In certain instances, fiberglass,
carbon fiber, or other composites may be used. See Class
Requirements or consult NHRA. Use of magnesium prohibited.

The rule book is readily available.

You need to ask a little more specific question.
Here is one section from the IHRA 2011 rule book in the general regulations. Check the class specific regs for the class you want to run and ET/mph.

It helps to pick up a SFI chassis book for your class too.

http://www.sfifoundation.com/

I don't know if the rules changed again in the last 2 years for my Duster chassis(SFI 25-1) but the aluminum firewall in it, is supposed to steel now.

Well ...I should check-in on my own topic ....... ...THX guyz ......

This situation is on my Caravan project ....I am going to set the motor back INTO the driver's compartment ...like near where the normal front-seating is ...and then drive-it from the typical second seating location....using the driver and passenger rear slider doors to enter and exit the vehicle.

Does this change anything here ? ANY other thoughts ?

I'd move the driver seat up further..otherwise you'll end up with a real long steering column.

The loooong steerimg column is a given ....better to have to deal with that than having to move the steering in the "K-member" forward....and remove and relocate all of that.

You'll have to build a dog house out of .024 steel or .032 aluminum. You'll also have to cage it because the firewall/floor is modified.

slant ... what would be the weight and maybe cost diff(in material) ... between alum and steel.

Also ... a cage ? ... to run AT ALL at any sanctioned track? ... or for a certain ET ? ...and if that is a blank-statement .. how many points in the car does it have to be ?

I am looking at the car running maybe 12-flat/high 11's or so. I had really THOUGHT about putting in a cage at-the-start(running all the way up to the front struts) ... but looking at the OEM floor and the way the whole vehicle is built .... with the front-to-rear(almost 2x4 longitudinals) ...I don't think it is really needed.

All in all ... the project(on the surface) seems A LOT simpler than I thought of before.

If it's only going to run high 11's you might get away w/o a cage. Personally I'd want at least an 8 point with all that glass area around me.

Depending on how big the firewall/doghouse end up being I'd think the weight difference would be in the 20# range.

There used to be a guy on the board with a Caravan that had a small block in the pretty much stock location. I think his name was 'Scaredvan' or something like that.