How about making a Double throttle body setup for the 420A using the stock manifold. I was thinking just machine a hole where the MAS or MAF or MAP(whatever it is) and attach another TB right there, than make another attachmant point somewhere on the Manifold for the MAS... Than just make an intake that fits in that area and voila, 2 intakes. What do you think, ideas?
The amount of work involved wouldn't be worth the gains. How are you going to get the TB to mount to a cast manifold? The best thing is either make a custom piece that replaces the top half or custom fit these: http://www.hilborninjection.com/product.asp?Id=58&CatId=39
Yeah, someone already making a quad TB for the neons using that. I cant look at the manifold since Im away from my car, so I was just taking a stab, maybe when I get home I can make a better idea!