BByrd, a couple of thoughts.
First, if you insist on the use of components that were designed back in the sixties, you should expect to get '60s numbers from the dyno. New-design heads, with their greater combustion-chamber efficiency, coupled with the new runner profiles that then become available, will give a significant numbers boost. Particularly if you use the flow studies you do as the basis for your camshaft design. You need to start with a 21st Century perspective.
I have done a number of EFI conversions on FEs. Working with the Holley development people, I did the first dual-throttle-body installation on a MR 427, back when EFI conversions were just becoming available. On a street '67 Mustang, the Holley dual throttle bodies were good for almost two seconds reduction from 1500 to 6000 in second gear. That's over ANY pair of carbs. The project resulted in an ongoing series of articles I wrote for Super Ford Magazine. I'll never use a carburetor again.
KS