Very good advice...
If you really want a "stock" look... maybe you could even pick up a 4 barrel stock manifold at a swap meet or salvage yard. You will lose performance, but keep the appearance.
Otherwise, a 600 cfm holley with vacuum secondaries and a Performer 289 will be a great addition... for around $400
Intake:
http://www.jegs.com/cgi-bin/ncommerc...20&prmenbr=361
Carb:
http://www.jegs.com/cgi-bin/ncommerc...55&prmenbr=361