The fresh air box in my mind is just something that would seal to the bottom of the hood, it doesn't have to be fancy. Once you sort out how to to filter the incoming air before it gets to the throttle body, constructing the box would be pretty straight-forward, I would think. For that matter, the throttle body doesn't have to STAY bolted up to the intake, it COULD be relocated with some form of adapter to some place more convenient if necessary. That would require some more complicated fabrication, but certainly do-able. There are all kinds of neat air fliter elements out there these days, from cone to flat round to square panel, all kinds of things to work with.
As for wishing I had these problems, it's the New Hemi problems I'm wishing I had. I'm just doing an EFI retrofit on my 340, and watching closely as my nearly-neighbor Daty deals with all the pain of the Hemi install. Fact is, I was looking VERY closely at installing a 4.7L OHC in my Valiant 4-5 years ago, and if I hadn't trusted some bad information I got about the bell housing bolt patterns, I might have done that rather than my 340. Upgrading to a Hemi after the 4.7 would have been pretty easy, I bet.
