Well, if you opt for a steel cowl induction hood, you won't have to fab up an airbox, just add an open cowl induction air cleaner with rubber seal.
http://www.ebay.com/itm/1970-72-Che...ash=item51c3ce7024:g:1MAAAOSwMmBVqajK&vxp=mtr
On the other hand, using a fiberglass cowl hood, it will have an open plenum and you would have to form an airbox to establish a fresh air induction system.
