Regarding the throttle body, I agree with Siggy. Depending on the cam you install, you may get by with just higher fuel pressure. You can get a 670 cfm TBI unit from a variety of sources. Also, chances are a custom chip will be in order.
I found a great TBI source at www.cfm-tech.com I am sure that there are plenty of other sources, but they seem to have a tailored selection for what you are attempting to do. Also check out Howell Engine Development